Update modern-control-combobox.md

Author: fafuxa-ms

powerapps-docs/maker/canvas-apps/controls/modern-controls/modern-control-combobox.md

@@ -18,7 +18,7 @@ contributors:
   - noazarur-microsoft
 
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-# Combobox modern control in Power Apps
+# Combobox modern control in Power Apps (preview)
 
 A control that allows users to make selections from provided choices and supports search and multiple selections.