[vcpkg manifest] Add documentation! (#13488)

* [vcpkg docs] add docs for manifest files

These are just for the maintainer docs,
not user docs.

* [vcpkg] EBNF-ify platform expression parsing

this modifies nothing about what strings are accepted or rejected,
it just moves stuff around.

also adds tests.

* [vcpkg docs] add manifest mode example

* [wip] docs for augustin

also fix tabs

* [vcpkg manifest] switch to using maps for features

* Apply suggestions from code review

* un-experimentize format-manifest

* flesh out the user manifest mode docs

* CRs

* billy CRs

* final personal pass-thru

1 files changed, 5 insertions, 8 deletions

diff --git a/ports/colmap/vcpkg.json b/ports/colmap/vcpkg.json
index 565e945ba..6feee3ee0 100644
--- a/ports/colmap/vcpkg.json
+++ b/ports/colmap/vcpkg.json
@@ -32,24 +32,21 @@
     "qt5-base",
     "suitesparse"
   ],
-  "features": [
-    {
-      "name": "cuda",
+  "features": {
+    "cuda": {
       "description": "CUDA support for current compute architecture of this machine.",
       "dependencies": [
         "cuda"
       ]
     },
-    {
-      "name": "cuda-redist",
+    "cuda-redist": {
       "description": "Redistributable CUDA support for common supported compute architectures.",
       "dependencies": [
         "cuda"
       ]
     },
-    {
-      "name": "tests",
+    "tests": {
       "description": "Enable TESTS."
     }
-  ]
+  }
 }