vim-patch:9.1.0573: ex: no implicit print for single addresses

Problem:  ex: no implicit print for single addresses
Solution: explicitly print even during single addresses,
          as requested by POSIX (Mohamed Akram)

See the POSIX behaviour here:
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ex.html#tag_20_40_13_03
Section 6b

closes: vim/vim#15230

c25a7084e9

Co-authored-by: Mohamed Akram <mohd.akram@outlook.com>

test/old/testdir/setup.vim

@@ -32,8 +32,8 @@ if exists('s:did_load')
   endif
   if g:testname !~ 'test_mapping.vim$'
     " Make "Q" switch to Ex mode.
-    " This does not work for all tests.
-    nnoremap Q gQ
+    " This does not work for all tests as Nvim only supports Vim Ex mode.
+    nnoremap Q gQ<Cmd>call<SID>ExStart()<CR>
   endif
 endif
 
@@ -45,6 +45,21 @@ if exists('s:did_load')
 endif
 let s:did_load = 1
 
+func s:ExStart()
+  call feedkeys($"\<Cmd>call{expand('<SID>')}ExMayEnd()\<CR>")
+endfunc
+
+func s:ExMayEnd()
+  " When :normal runs out of characters in Vim, the behavior is different in
+  " normal Ex mode vs. Vim Ex mode.
+  " - In normal Ex mode, "\n" is used.
+  " - In Vim Ex mode, Ctrl-C is used.
+  " Nvim only supports Vim Ex mode, so emulate the normal Ex mode behavior.
+  if state('m') == '' && mode(1) == 'cv' && getcharstr(1) == "\<C-C>"
+    call feedkeys("\n")
+  endif
+endfunc
+
 " Clear Nvim default user commands, mappings and menus.
 comclear
 mapclear