docs: adds instructions for the typespec annotations

Signed-off-by: Vincent Biret <vibiret@microsoft.com>

Author: baywet

additions/README.md

@@ -0,0 +1,21 @@
+# TypeSpec annotations additions
+
+This TypeSpec project allows you to define additional annotations to inject in the CSDL files. It's an alternative to the XLST in `/transform`.
+The copy scripts (in `/scripts/copy-annotations-to-csdl.ps1`) ONLY considers annotations, and DOES NOT perform any deduplication other than the ones enforced by XML keys.
+
+## Requirements
+
+- Node 22.x or above
+- TypeScript `npm i -g typescript`
+- TypeSpec compiler `npm i -g @typespec/compiler`
+- dependencies installed `npm ci`
+- vscode (or equivalent) `sudo winget install Microsoft.VisualStudioCode`
+
+## Getting started
+
+1. Make changes to the TypeSpec (.tsp) file
+1. Run the compilation `tsp compile . --watch`
+1. Run the copy scripts `.\scripts\copy-annotations-to-csdl.ps1 -sourceCsdlDirectoryPath $pwd\additions\tsp-output -targetCsdlPath $pwd\clean_v10_metadata\cleanMetadataWithDescriptionsAndAnnotationsAndErrorsv1.0.xml`
+1. Diff the changes to ensure this is what you expect
+
+> Note: Do not commit any changes to the target CSDL as those are generated weekly.