Configure api extractor for json schema and add docs and refactor (#4732

)

Configure api extractor and add docs. Additionally refactored to use
some newer pattern of decorator declaration.

.chronus/changes/json-schema-api-extractor-2024-9-14-22-42-24.md

@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@typespec/json-schema"
+---
+
+Document exported types

packages/json-schema/api-extractor.json

@@ -0,0 +1,4 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/api-extractor/v7/api-extractor.schema.json",
+  "extends": "../../api-extractor.base.json"
+}

packages/json-schema/package.json

@@ -36,7 +36,7 @@
   },
   "scripts": {
     "clean": "rimraf ./dist ./temp",
-    "build": "npm run gen-extern-signature && tsc -p . && npm run lint-typespec-library",
+    "build": "npm run gen-extern-signature && tsc -p . && npm run lint-typespec-library && pnpm api-extractor",
     "watch": "tsc -p . --watch",
     "gen-extern-signature": "tspd --enable-experimental gen-extern-signature .",
     "lint-typespec-library": "tsp compile . --warn-as-error --import @typespec/library-linter --no-emit",
@@ -45,7 +45,8 @@
     "test:ci": "vitest run --coverage --reporter=junit --reporter=default",
     "lint": "eslint . --max-warnings=0",
     "lint:fix": "eslint . --fix",
-    "regen-docs": "tspd doc .  --enable-experimental  --output-dir ../../docs/emitters/json-schema/reference"
+    "regen-docs": "tspd doc .  --enable-experimental  --output-dir ../../docs/emitters/json-schema/reference",
+    "api-extractor": "api-extractor run --local --verbose"
   },
   "files": [
     "lib/*.tsp",