Introduce comments below events

Also add tomstones

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/typings/tiptap.d.ts

@@ -2,6 +2,9 @@ declare module 'tiptap' {
     import Vue from 'vue';
     export class Editor {
       public constructor({});
+      public commands: {
+        mention: Function,
+      };
 
       public setOptions({}): void;
       public setContent(content: string): void;