Editor: Close proposal widget when text is pasted

Already worked with the shortcut defined in the settings, but not with
the standard shortcuts defined by QKeySequence.

Task-number: QTCREATORBUG-16586
Change-Id: I4dc02e29ee5d273c3bfc9de28f52e90cffc2397c
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/texteditor/codeassist/genericproposalwidget.cpp

@@ -621,7 +621,7 @@ bool GenericProposalWidget::eventFilter(QObject *o, QEvent *e)
 
         default:
             // Only forward keys that insert text and refine the completion.
-            if (ke->text().isEmpty())
+            if (ke->text().isEmpty() && !(ke == QKeySequence::Paste))
                 return true;
             break;
         }