👍 Add interrupted attribute

vim-denops/denops.vim#348

Author: lambdalisue

denops.ts

@@ -74,6 +74,11 @@ export interface Denops {
    */
   readonly context: Record<PropertyKey, unknown>;
 
+  /**
+   * AbortSignal instance that is triggered when the user invoke `denops#interrupt()`
+   */
+  readonly interrupted: AbortSignal;
+
   /**
    * User-defined API name and method map used to dispatch API requests.
    */