style: remake updateUI into flushUI

app/assets/javascripts/views/abstract/pure_view_ctrl.ts

@@ -69,8 +69,9 @@ export class PureViewCtrl<P = CtrlProps, S = CtrlState> {
     });
   }
 
-  async updateUI(func: () => void) {
-    this.$timeout(func);
+  /** @returns a promise that resolves after the UI has been updated. */
+  flushUI() {
+    return this.$timeout();
   }
 
   initProps(props: CtrlProps) {

app/assets/javascripts/views/editor/editor_view.ts

@@ -779,12 +779,11 @@ class EditorViewCtrl extends PureViewCtrl<{}, EditorState> {
     );
   }
 
-  reloadTagsString() {
+  async reloadTagsString() {
     const tags = this.appState.getNoteTags(this.note);
     const string = SNTag.arrayToDisplayString(tags);
-    this.updateUI(() => {
-      this.editorValues.tagsInputValue = string;
-    })
+    await this.flushUI();
+    this.editorValues.tagsInputValue = string;
   }
 
   private addTag(tag: SNTag) {