Cleanup: Remove searchKeywords from optionspage widgets

If no specialization is provided then the UI strings are searched.

So get rid of extra code collecting all those strings in a lot of
places.

Change-Id: Ibcb48a67e5c7b74e5960fe38b1cb2f74259b503a
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/texteditor/codestyleselectorwidget.cpp

@@ -432,10 +432,4 @@ QString CodeStyleSelectorWidget::displayName(ICodeStylePreferences *codeStyle) c
     return name;
 }
 
-QString CodeStyleSelectorWidget::searchKeywords() const
-{
-    // no useful keywords here
-    return QString();
-}
-
 #include "codestyleselectorwidget.moc"