src/vs/editor/common/languages/languageConfigurationRegistry.ts/ResolvedLanguageConfiguration/onEnter
class ResolvedLanguageConfiguration:	public onEnter(
		autoIndent: EditorAutoIndentStrategy,
		previousLineText: string,
		beforeEnterText: string,
		afterEnterText: string
	): EnterAction | null {
		if (!this._onEnterSupport) {
			return null;
		}
		return this._onEnterSupport.onEnter(
			autoIndent,
			previousLineText,
			beforeEnterText,
			afterEnterText
		);
	}