patch 9.0.1855: mode() doesn't indicate command line for terminal

Problem:  mode() doesn't indicate command line for terminal
Solution: make it return 'ct' for command-line from Terminal mode

closes: #6265
closes: #13017
closes: #13018

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: h-east <h.east.727@gmail.com>

runtime/doc/builtin.txt

@@ -6408,6 +6408,7 @@ mode([expr])	Return a string that indicates the current mode.
 		   Rvc	    Virtual Replace mode completion |compl-generic|
 		   Rvx	    Virtual Replace mode |i_CTRL-X| completion
 		   c	    Command-line editing
+		   ct	    Command-line editing via Terminal-Job mode
 		   cv	    Vim Ex mode |gQ|
 		   ce	    Normal Ex mode |Q|
 		   r	    Hit-enter prompt

src/misc1.c

@@ -664,7 +664,11 @@ get_mode(char_u *buf)
     }
 #ifdef FEAT_TERMINAL
     else if (term_use_loop())
+    {
+	if (State & MODE_CMDLINE)
+	    buf[i++] = 'c';
 	buf[i++] = 't';
+    }
 #endif
     else if (VIsual_active)
     {

src/testdir/test_functions.vim

@@ -935,9 +935,19 @@ func Test_mode()
 
   if has('terminal')
     term
+    " Terminal-Job mode
+    call assert_equal('t', mode())
+    call assert_equal('t', mode(1))
+    call feedkeys("\<C-W>:echo \<C-R>=Save_mode()\<C-U>\<CR>", 'xt')
+    call assert_equal("c-ct", g:current_modes)
+    call feedkeys("\<Esc>", 'xt')
+
+    " Terminal-Normal mode
     call feedkeys("\<C-W>N", 'xt')
     call assert_equal('n', mode())
     call assert_equal('nt', mode(1))
+    call feedkeys(":echo \<C-R>=Save_mode()\<C-U>\<CR>", 'xt')
+    call assert_equal("c-c", g:current_modes)
     call feedkeys("aexit\<CR>", 'xt')
   endif
 

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1855,
 /**/
     1854,
 /**/