UI text: make QML option label shorter

The same information is already given in the dialog
title. Fix capitalization of OK.

Change-Id: Ia77bd62075f8553a8533edbe56965cf662541cc7
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>

src/plugins/qmldesigner/designercore/filemanager/qmlwarningdialog.ui

@@ -67,7 +67,7 @@
    <item>
     <widget class="QCheckBox" name="checkBox">
      <property name="text">
-      <string>Warn about QML features which are not properly supported by the Qt Quick Designer</string>
+      <string>Warn about unsupported features</string>
      </property>
     </widget>
    </item>
@@ -99,7 +99,7 @@
      <item>
       <widget class="QPushButton" name="okButton">
        <property name="text">
-        <string>Ok</string>
+        <string>OK</string>
        </property>
       </widget>
      </item>