Use the MRU window height for the FZF window

plugin/mru.vim

@@ -1006,7 +1006,7 @@ func s:MRU_FZF_Run() abort
   endif
   call fzf#run(fzf#wrap({'source' : s:MRU_files,
 	\ 'sink' : function('s:MRU_FZF_EditFile'),
-	\'down' : '25%'}, 0))
+	\ 'down' : g:MRU_Window_Height}, 0))
 endfunc
 command! -nargs=0 FZFMru call s:MRU_FZF_Run()