Use ClassicAPI's nop for empty functions

modules/addoncompat.lua

@@ -128,7 +128,7 @@ pfUI:RegisterModule("addoncompat", function ()
         {T["Yes"], function()
           ReloadUI()
         end},
-        {T["No"], function() end},
+        {T["No"], nop},
         nil)
     end
   end

modules/gui.lua

@@ -761,7 +761,7 @@ pfUI:RegisterModule("gui", function ()
       local defval = "["..T["Search"].."]"
 
       -- initialize search window
-      CreateGUIEntry(defval, nil, function() end)
+      CreateGUIEntry(defval, nil, nop)
       pfUI.gui.frames[defval]:Click()
 
       local scroll = pfUI.gui.frames[defval].area.scroll.content