Add .har extension

src/monaco.contribution.ts

@@ -67,7 +67,7 @@ function getMode(): Promise<typeof mode> {
 
 monaco.languages.register({
 	id: 'json',
-	extensions: ['.json', '.bowerrc', '.jshintrc', '.jscsrc', '.eslintrc', '.babelrc'],
+	extensions: ['.json', '.bowerrc', '.jshintrc', '.jscsrc', '.eslintrc', '.babelrc', '.har'],
 	aliases: ['JSON', 'json'],
 	mimetypes: ['application/json'],
 });