Update rust grammar to be pulled from main branch (#194787)

Discovered through https://github.com/microsoft/vscode/pull/194758

extensions/rust/build/update-grammar.mjs

@@ -0,0 +1,9 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+//@ts-check
+
+import * as vscodeGrammarUpdater from 'vscode-grammar-updater';
+
+vscodeGrammarUpdater.update('dustypomerleau/rust-syntax', 'syntaxes/rust.tmLanguage.json', './syntaxes/rust.tmLanguage.json', undefined, 'main');

extensions/rust/package.json

@@ -9,7 +9,7 @@
     "vscode": "*"
   },
   "scripts": {
-    "update-grammar": "node ../node_modules/vscode-grammar-updater/bin dustypomerleau/rust-syntax syntaxes/rust.tmLanguage.json ./syntaxes/rust.tmLanguage.json"
+    "update-grammar": "node ./build/update-grammar.mjs"
   },
   "contributes": {
     "languages": [

extensions/rust/syntaxes/rust.tmLanguage.json

@@ -888,7 +888,7 @@
 			"patterns": [
 				{
 					"comment": "namespace (non-type, non-function path segment)",
-					"match": "(?<![A-Za-z0-9_])([a-z0-9_]+)((?<!super|self)::)",
+					"match": "(?<![A-Za-z0-9_])([A-Za-z0-9_]+)((?<!super|self)::)",
 					"captures": {
 						"1": {
 							"name": "entity.name.namespace.rust"