Update control-richtexteditor.md

Adding limitation that it's only supported in preview mode.

Author: chmoncay

powerapps-docs/maker/canvas-apps/controls/control-richtexteditor.md

@@ -76,5 +76,8 @@ To use the control inside a form, select the "Edit multi-line text" card, and cu
 > [!NOTE]
 > When the toolbar is focused, **Tab** and **Shift+Tab** keys will navigate between toolbar groups. But you can't cycle back from the last group to the first group and vice versa.
 
+## Limitations
+### Studio support
+The rich text editor control can only be interacted with in preview mode.
 
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