Convert files to typescript

The change converts the following files to typescript:

* elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts

Change-Id: I274ba656285897c89c42f299724e402758b8cfe3

polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts

diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
index bc7e739..f1af68d 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
@@ -49,6 +49,7 @@
   CommentInfo,
   ConfigInfo,
   AccountDetailInfo,
+  ChangeNum,
 } from '../../../types/common';
 import {GrButton} from '../gr-button/gr-button';
 import {GrConfirmDeleteCommentDialog} from '../gr-confirm-delete-comment-dialog/gr-confirm-delete-comment-dialog';
@@ -96,6 +97,10 @@
 export type Comment = Draft & CommentInfo;
 export type RobotComment = Draft & RobotCommentInfo;
 
+export function isRobotComment(c: Comment | RobotComment): c is RobotComment {
+  return (c as RobotComment).robot_id !== undefined;
+}
+
 interface CommentOverlays {
   confirmDelete?: GrOverlay | null;
   confirmDiscard?: GrOverlay | null;
@@ -109,6 +114,12 @@
     resolvedCheckbox: HTMLInputElement;
   };
 }
+
+export interface CommentEventDetail {
+  patchNum?: PatchSetNum;
+  comment?: Comment | RobotComment;
+}
+
 @customElement('gr-comment')
 export class GrComment extends KeyboardShortcutMixin(
   GestureEventListeners(LegacyElementMixin(PolymerElement))
@@ -160,7 +171,7 @@
    */
 
   @property({type: Number})
-  changeNum?: number;
+  changeNum?: ChangeNum;
 
   @property({type: Object, notify: true, observer: '_commentChanged'})
   comment?: Comment | RobotComment;
@@ -506,8 +517,8 @@
     );
   }
 
-  _getEventPayload(opt_mixin?: Record<string, any>) {
-    return {...opt_mixin, comment: this.comment, patchNum: this.patchNum};
+  _getEventPayload(): CommentEventDetail {
+    return {comment: this.comment, patchNum: this.patchNum};
   }
 
   _fireSave() {