Restore extensions in core (#114921)

* bring back grammar extensions

* fix hygiene

* Revert "pull themes from the marketplace"

This reverts commit 0738f76dac.

extensions/typescript-basics/syntaxes/Readme.md

@@ -0,0 +1,16 @@
+The file `TypeScript.tmLanguage.json` and `TypeScriptReact.tmLanguage.json` are derived from [TypeScript.tmLanguage](https://github.com/microsoft/TypeScript-TmLanguage/blob/master/TypeScript.tmLanguage) and [TypeScriptReact.tmLanguage](https://github.com/microsoft/TypeScript-TmLanguage/blob/master/TypeScriptReact.tmLanguage).
+
+To update to the latest version:
+- `cd extensions/typescript` and run `npm run update-grammars`
+- don't forget to run the integration tests at `./scripts/test-integration.sh`
+
+Migration notes and todos:
+
+- differentiate variable and function declarations from references
+  - I suggest we use a new scope segment 'function-call' to signal a function reference, and 'definition' to the declaration. An alternative is to use 'support.function' everywhere.
+  - I suggest we use a new scope segment 'definition' to the variable declarations. Haven't yet found a scope for references that other grammars use.
+
+- rename scope to return.type to return-type, which is already used in other grammars
+- rename entity.name.class to entity.name.type.class which is used in all other grammars I've seen
+
+- do we really want to have the list of all the 'library' types (Math, Dom...). It adds a lot of size to the grammar, lots of special rules and is not really correct as it depends on the JavaScript runtime which types are present.

extensions/typescript-basics/syntaxes/jsdoc.js.injection.tmLanguage.json

@@ -0,0 +1,21 @@
+
+{
+	"injectionSelector": "L:comment.block.documentation",
+	"patterns": [
+		{
+			"include": "#jsdocbody"
+		}
+	],
+	"repository": {
+		"jsdocbody": {
+			"begin": "(?<=/\\*\\*)([^*]|\\*(?!/))*$",
+			"while": "(^|\\G)\\s*\\*(?!/)(?=([^*]|[*](?!/))*$)",
+			"patterns": [
+				{
+					"include": "source.ts#docblock"
+				}
+			]
+		}
+	},
+	"scopeName": "documentation.injection.js.jsx"
+}

extensions/typescript-basics/syntaxes/jsdoc.ts.injection.tmLanguage.json

@@ -0,0 +1,21 @@
+
+{
+	"injectionSelector": "L:comment.block.documentation",
+	"patterns": [
+		{
+			"include": "#jsdocbody"
+		}
+	],
+	"repository": {
+		"jsdocbody": {
+			"begin": "(?<=/\\*\\*)([^*]|\\*(?!/))*$",
+			"while": "(^|\\G)\\s*\\*(?!/)(?=([^*]|[*](?!/))*$)",
+			"patterns": [
+				{
+					"include": "source.ts#docblock"
+				}
+			]
+		}
+	},
+	"scopeName": "documentation.injection.ts"
+}