vim-patch:8.0.0609: some people still don't know how to quit (#8571)

Problem:    For some people the hint about quitting is not sufficient.
Solution:   Put <Enter> separately.  Also use ":qa!" to get out even when
            there are changes.
28a8193e31

test/functional/ui/cmdline_highlight_spec.lua

@@ -494,7 +494,7 @@ describe('Command-line coloring', function()
       {EOB:~                                       }|
       {EOB:~                                       }|
       {EOB:~                                       }|
-      Type  :quit<Enter>  to exit Nvim        |
+      Type  :qa!  and pr...nges and exit Nvim |
     ]])
   end)
   it('works fine with NUL, NL, CR', function()