[cpp] add platform.tmLanguage to update list, consistent file names

extensions/cpp/build/update-grammars.js

+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+var updateGrammar = require('../../../build/npm/update-grammar');
+
+updateGrammar.update('atom/language-c', 'grammars/c.cson', './syntaxes/c.tmLanguage.json');
+updateGrammar.update('atom/language-c', 'grammars/c%2B%2B.cson', './syntaxes/cpp.tmLanguage.json');
+
+// `source.c.platform` which is still included by other grammars
+updateGrammar.update('textmate/c.tmbundle', 'Syntaxes/Platform.tmLanguage', './syntaxes/platform.tmLanguage.json');
+