Adding new topic per 1962430

Author: Mattp123

powerapps-docs/maker/TOC.yml

@@ -1171,6 +1171,8 @@
           href: ./model-driven-apps/timer-control-legacy.md
         - name: Add the calendar control to entities
           href: ./model-driven-apps/add-calendar-control.md
+        - name: Add the rich text editor control
+          href: ./model-driven-apps/rich-text-editor-control.md
         - name: Add the news control to an entity
           href: ./model-driven-apps/stay-current-with-news-control.md          
       - name: Use custom controls for data visualizations