Add proper contribution schema for ts server pluguins

#50682

extensions/typescript-language-features/package.json

@@ -44,6 +44,12 @@
   ],
   "main": "./out/extension",
   "contributes": {
+    "jsonValidation": [
+      {
+        "fileMatch": "package.json",
+        "url": "./schemas/package.schema.json"
+      }
+    ],
     "configuration": {
       "type": "object",
       "title": "%configuration.typescript%",

extensions/typescript-language-features/schemas/package.schema.json

@@ -0,0 +1,26 @@
+{
+	"$schema": "http://json-schema.org/draft-04/schema#",
+	"title": "TypeScript contributions to package.json",
+	"type": "object",
+	"properties": {
+		"contributes": {
+			"type": "object",
+			"properties": {
+				"typescriptServerPlugins": {
+					"type": "array",
+					"description": "Contributed TypeScript server plugins.",
+					"items": {
+						"type": "object",
+						"description": "TypeScript server plugin.typescriptServerPlugins",
+						"properties": {
+							"name": {
+								"type": "string",
+								"description": "The name of the plugin as listed in the package.json."
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+}