[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, 3 insertions, 4 deletions

diff --git a/ports/numcpp/vcpkg.json b/ports/numcpp/vcpkg.json
index db31f6a3b..dab0d3abc 100644
--- a/ports/numcpp/vcpkg.json
+++ b/ports/numcpp/vcpkg.json
@@ -13,14 +13,13 @@
     "boost-random",
     "boost-type-traits"
   ],
-  "features": [
-    {
-      "name": "python",
+  "features": {
+    "python": {
       "description": "Interacting with python with pybind11 interface",
       "dependencies": [
         "boost-python",
         "pybind11"
       ]
     }
-  ]
+  }
 }