adds experimental tag to editor.experimental.asyncTokenization (microsoft#175296)

Author: hediet

src/vs/editor/common/config/editorConfigurationSchema.ts

@@ -98,7 +98,8 @@ const editorConfiguration: IConfigurationNode = {
 		'editor.experimental.asyncTokenization': {
 			type: 'boolean',
 			default: false,
-			description: nls.localize('editor.experimental.asyncTokenization', "Controls whether the tokenization should happen asynchronously on a web worker.")
+			description: nls.localize('editor.experimental.asyncTokenization', "Controls whether the tokenization should happen asynchronously on a web worker."),
+			tags: ['experimental'],
 		},
 		'editor.language.brackets': {
 			type: ['array', 'null'],