src/vs/workbench/api/browser/mainThreadLanguageFeatures.ts/MainThreadLanguageFeatures/$registerOnTypeFormattingSupport
class MainThreadLanguageFeatures:	$registerOnTypeFormattingSupport(handle: number, selector: IDocumentFilterDto[], autoFormatTriggerCharacters: string[], extensionId: ExtensionIdentifier): void {
		this._registrations.set(handle, modes.OnTypeFormattingEditProviderRegistry.register(selector, <modes.OnTypeFormattingEditProvider>{
			extensionId,
			autoFormatTriggerCharacters,
			provideOnTypeFormattingEdits: (model: ITextModel, position: EditorPosition, ch: string, options: modes.FormattingOptions, token: CancellationToken): Promise<ISingleEditOperation[] | undefined> => {
				return this._proxy.$provideOnTypeFormattingEdits(handle, model.uri, position, ch, options, token);
			}
		}));
	}