Use in API and utilities WKT2_2019 instead of WKT2_2018 (fixes #1518)

- C API: PJ_GUESSED_WKT2_2019 is added, PJ_GUESSED_WKT2_2018 aliased to it
- C API: PJ_WKT2_2019[_SIMPLIFIED] is added, PJ_WKT2_2018[_SIMPLIFIED] alias to it
- C++ API: similarly for WKTFormatter::Convention::WKT2_2019[_SIMPLIFIED]
Those above changes should be fully backward API and ABI compatible.

projinfo changes:
- accept WKT2_2019 as value for -o switch. WKT2_2018 is still accepted (undocumented)
- output now uses 'WKT2_2019 string:', so might break scripts that would rely on that.

Other internal code references to WKT2_2018 changes to WKT2_2019, included
in tests.

4 files changed, 42 insertions, 34 deletions

diff --git a/include/proj/coordinatesystem.hpp b/include/proj/coordinatesystem.hpp
index ffb908fc..573f18e2 100644
--- a/include/proj/coordinatesystem.hpp
+++ b/include/proj/coordinatesystem.hpp
@@ -623,7 +623,7 @@ class PROJ_GCC_DLL TemporalCS : public CoordinateSystem {
     INLINED_MAKE_SHARED
 
     PROJ_INTERNAL std::string
-    getWKT2Type(bool use2018Keywords) const override = 0;
+    getWKT2Type(bool use2019Keywords) const override = 0;
 
   private:
     TemporalCS(const TemporalCS &other) = delete;
@@ -661,7 +661,7 @@ class PROJ_GCC_DLL DateTimeTemporalCS final : public TemporalCS {
         const CoordinateSystemAxisNNPtr &axis);
     INLINED_MAKE_SHARED
 
-    PROJ_INTERNAL std::string getWKT2Type(bool use2018Keywords) const override;
+    PROJ_INTERNAL std::string getWKT2Type(bool use2019Keywords) const override;
 
   private:
     DateTimeTemporalCS(const DateTimeTemporalCS &other) = delete;
@@ -697,7 +697,7 @@ class PROJ_GCC_DLL TemporalCountCS final : public TemporalCS {
         const CoordinateSystemAxisNNPtr &axis);
     INLINED_MAKE_SHARED
 
-    PROJ_INTERNAL std::string getWKT2Type(bool use2018Keywords) const override;
+    PROJ_INTERNAL std::string getWKT2Type(bool use2019Keywords) const override;
 
   private:
     TemporalCountCS(const TemporalCountCS &other) = delete;
@@ -733,7 +733,7 @@ class PROJ_GCC_DLL TemporalMeasureCS final : public TemporalCS {
         const CoordinateSystemAxisNNPtr &axis);
     INLINED_MAKE_SHARED
 
-    PROJ_INTERNAL std::string getWKT2Type(bool use2018Keywords) const override;
+    PROJ_INTERNAL std::string getWKT2Type(bool use2019Keywords) const override;
 
   private:
     TemporalMeasureCS(const TemporalMeasureCS &other) = delete;
diff --git a/include/proj/crs.hpp b/include/proj/crs.hpp
index b83e0a6b..7062885d 100644
--- a/include/proj/crs.hpp
+++ b/include/proj/crs.hpp
@@ -1352,7 +1352,7 @@ struct PROJ_GCC_DLL DerivedEngineeringCRSTraits {
     inline static const std::string &CRSName();
     inline static const std::string &WKTKeyword();
     inline static const std::string &WKTBaseKeyword();
-    static const bool wkt2_2018_only = true;
+    static const bool wkt2_2019_only = true;
 };
 //! @endcond
 
@@ -1390,7 +1390,7 @@ struct PROJ_GCC_DLL DerivedParametricCRSTraits {
     inline static const std::string &CRSName();
     inline static const std::string &WKTKeyword();
     inline static const std::string &WKTBaseKeyword();
-    static const bool wkt2_2018_only = false;
+    static const bool wkt2_2019_only = false;
 };
 //! @endcond
 
@@ -1427,7 +1427,7 @@ struct PROJ_GCC_DLL DerivedTemporalCRSTraits {
     inline static const std::string &CRSName();
     inline static const std::string &WKTKeyword();
     inline static const std::string &WKTBaseKeyword();
-    static const bool wkt2_2018_only = false;
+    static const bool wkt2_2019_only = false;
 };
 //! @endcond
 
diff --git a/include/proj/internal/io_internal.hpp b/include/proj/internal/io_internal.hpp
index bd6d441d..781dfa6c 100644
--- a/include/proj/internal/io_internal.hpp
+++ b/include/proj/internal/io_internal.hpp
@@ -87,8 +87,8 @@ class WKTConstants {
     static const std::string CONVERSION;
     static const std::string METHOD;
     static const std::string REMARK;
-    static const std::string GEOGCRS;     // WKT2-2018
-    static const std::string BASEGEOGCRS; // WKT2-2018
+    static const std::string GEOGCRS;     // WKT2-2019
+    static const std::string BASEGEOGCRS; // WKT2-2019
     static const std::string SCOPE;
     static const std::string AREA;
     static const std::string BBOX;
@@ -103,27 +103,27 @@ class WKTConstants {
     static const std::string TARGETCRS;
     static const std::string INTERPOLATIONCRS;
     static const std::string OPERATIONACCURACY;
-    static const std::string CONCATENATEDOPERATION; // WKT2-2018
-    static const std::string STEP;                  // WKT2-2018
+    static const std::string CONCATENATEDOPERATION; // WKT2-2019
+    static const std::string STEP;                  // WKT2-2019
     static const std::string BOUNDCRS;
     static const std::string ABRIDGEDTRANSFORMATION;
     static const std::string DERIVINGCONVERSION;
     static const std::string TDATUM;
-    static const std::string CALENDAR; // WKT2-2018
+    static const std::string CALENDAR; // WKT2-2019
     static const std::string TIMEORIGIN;
     static const std::string TIMECRS;
     static const std::string VERTICALEXTENT;
     static const std::string TIMEEXTENT;
-    static const std::string USAGE;            // WKT2-2018
-    static const std::string DYNAMIC;          // WKT2-2018
-    static const std::string FRAMEEPOCH;       // WKT2-2018
-    static const std::string MODEL;            // WKT2-2018
-    static const std::string VELOCITYGRID;     // WKT2-2018
-    static const std::string ENSEMBLE;         // WKT2-2018
-    static const std::string MEMBER;           // WKT2-2018
-    static const std::string ENSEMBLEACCURACY; // WKT2-2018
-    static const std::string DERIVEDPROJCRS;   // WKT2-2018
-    static const std::string BASEPROJCRS;      // WKT2-2018
+    static const std::string USAGE;            // WKT2-2019
+    static const std::string DYNAMIC;          // WKT2-2019
+    static const std::string FRAMEEPOCH;       // WKT2-2019
+    static const std::string MODEL;            // WKT2-2019
+    static const std::string VELOCITYGRID;     // WKT2-2019
+    static const std::string ENSEMBLE;         // WKT2-2019
+    static const std::string MEMBER;           // WKT2-2019
+    static const std::string ENSEMBLEACCURACY; // WKT2-2019
+    static const std::string DERIVEDPROJCRS;   // WKT2-2019
+    static const std::string BASEPROJCRS;      // WKT2-2019
     static const std::string EDATUM;
     static const std::string ENGCRS;
     static const std::string PDATUM;
@@ -140,11 +140,11 @@ class WKTConstants {
     static const std::string GEODETICDATUM;
     static const std::string PROJECTEDCRS;
     static const std::string PRIMEMERIDIAN;
-    static const std::string GEOGRAPHICCRS; // WKT2-2018
-    static const std::string TRF;           // WKT2-2018
+    static const std::string GEOGRAPHICCRS; // WKT2-2019
+    static const std::string TRF;           // WKT2-2019
     static const std::string VERTICALCRS;
     static const std::string VERTICALDATUM;
-    static const std::string VRF; // WKT2-2018
+    static const std::string VRF; // WKT2-2019
     static const std::string TIMEDATUM;
     static const std::string TEMPORALQUANTITY;
     static const std::string ENGINEERINGDATUM;
diff --git a/include/proj/io.hpp b/include/proj/io.hpp
index 5b1a8588..e439b9ef 100644
--- a/include/proj/io.hpp
+++ b/include/proj/io.hpp
@@ -182,18 +182,24 @@ class PROJ_GCC_DLL WKTFormatter {
         WKT2_SIMPLIFIED,
         WKT2_2015_SIMPLIFIED = WKT2_SIMPLIFIED,
 
-        /** Full WKT2 string, conforming to ISO 19162:2018 / OGC 18-010, with
-         * (\ref WKT2_2018) all possible nodes and new keyword names.
+        /** Full WKT2 string, conforming to ISO 19162:2019 / OGC 18-010, with
+         * (\ref WKT2_2019) all possible nodes and new keyword names.
          * Non-normative list of differences:
          * <ul>
-         *      <li>WKT2_2018 uses GEOGCRS / BASEGEOGCRS keywords for
+         *      <li>WKT2_2019 uses GEOGCRS / BASEGEOGCRS keywords for
          * GeographicCRS.</li>
          * </ul>
          */
-        WKT2_2018,
+        WKT2_2019,
 
-        /** WKT2_2018 with the simplification rule of WKT2_SIMPLIFIED */
-        WKT2_2018_SIMPLIFIED,
+        /** Deprecated alias for WKT2_2019 */
+        WKT2_2018 = WKT2_2019,
+
+        /** WKT2_2019 with the simplification rule of WKT2_SIMPLIFIED */
+        WKT2_2019_SIMPLIFIED,
+
+        /** Deprecated alias for WKT2_2019_SIMPLIFIED */
+        WKT2_2018_SIMPLIFIED = WKT2_2019_SIMPLIFIED,
 
         /** WKT1 as traditionally output by GDAL, deriving from OGC 01-009.
             A notable departure from WKT1_GDAL with respect to OGC 01-009 is
@@ -322,7 +328,7 @@ class PROJ_GCC_DLL WKTFormatter {
     };
 
     PROJ_INTERNAL Version version() const;
-    PROJ_INTERNAL bool use2018Keywords() const;
+    PROJ_INTERNAL bool use2019Keywords() const;
     PROJ_INTERNAL bool useESRIDialect() const;
 
     PROJ_INTERNAL const DatabaseContextPtr &databaseContext() const;
@@ -736,8 +742,10 @@ class PROJ_GCC_DLL WKTParser {
 
     /** Guessed WKT "dialect" */
     enum class PROJ_MSVC_DLL WKTGuessedDialect {
-        /** \ref WKT2_2018 */
-        WKT2_2018,
+        /** \ref WKT2_2019 */
+        WKT2_2019,
+        /** Deprecated alias for WKT2_2019 */
+        WKT2_2018 = WKT2_2019,
         /** \ref WKT2_2015 */
         WKT2_2015,
         /** \ref WKT1 */