The close button in reload prompt message box had no keyboard shortcut.
The text was changed to &Close to add the shortcut. This behavior is
useful after a long QtCreator session and several Qt intermediate files
open. When those files are regenerated it's useful to close them.

Change-Id: I25a9134eeed3ce6f10a5b698c7eda9f714f3bae5
Reviewed-by: David Schulz <david.schulz@theqtcompany.com>