CodeAssist: Expand prefix only when it's a completion

Quickfixes, for instance, should not be expanded.

Change-Id: I832ea11c5a270ee290441aca0d2c7231d0ced013
Reviewed-on: http://codereview.qt.nokia.com/674
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Christian Kamm <christian.d.kamm@nokia.com>

src/plugins/texteditor/codeassist/genericproposalwidget.h

@@ -52,6 +52,7 @@ public:
 
     virtual void setAssistant(CodeAssistant *assistant);
     virtual void setReason(AssistReason reason);
+    virtual void setKind(AssistKind kind);
     virtual void setUnderlyingWidget(const QWidget *underlyingWidget);
     virtual void setModel(IAssistProposalModel *model);
     virtual void setDisplayRect(const QRect &rect);