Force the dictionary popup to do a partial update.

It was done the other way around on purpose, so I probably broke some
very specific use-case ;). Feel free to shout at me ^^.

frontend/ui/widget/dictquicklookup.lua

@@ -257,7 +257,7 @@ function DictQuickLookup:update()
         }
     }
     UIManager.repaint_all = true
-    UIManager.full_refresh = true
+    UIManager.partial_refresh = true
 end
 
 function DictQuickLookup:isPrevDictAvaiable()