patch 8.2.2341: expresison command line completion incomplete after "g:"

Problem:    Expresison command line completion shows variables but not
            functions after "g:". (Gary Johnson)
Solution:   Prefix "g:" when needed to a global function.

src/evalfunc.c

@@ -1822,7 +1822,11 @@ get_function_name(expand_T *xp, int idx)
     {
 	name = get_user_func_name(xp, idx);
 	if (name != NULL)
+	{
+	    if (*name != '<' && STRNCMP("g:", xp->xp_pattern, 2) == 0)
+		return cat_prefix_varname('g', name);
 	    return name;
+	}
     }
     if (++intidx < (int)(sizeof(global_functions) / sizeof(funcentry_T)))
     {

src/evalvars.c

@@ -1952,7 +1952,7 @@ static int	varnamebuflen = 0;
 /*
  * Function to concatenate a prefix and a variable name.
  */
-    static char_u *
+    char_u *
 cat_prefix_varname(int prefix, char_u *name)
 {
     int		len;

src/proto/evalvars.pro

@@ -26,6 +26,7 @@ void ex_unletlock(exarg_T *eap, char_u *argstart, int deep, int glv_flags, int (
 int do_unlet(char_u *name, int forceit);
 void item_lock(typval_T *tv, int deep, int lock, int check_refcount);
 void del_menutrans_vars(void);
+char_u *cat_prefix_varname(int prefix, char_u *name);
 char_u *get_user_var_name(expand_T *xp, int idx);
 char *get_var_special_name(int nr);
 dict_T *get_globvar_dict(void);

src/testdir/test_cmdline.vim

@@ -619,6 +619,10 @@ func Test_cmdline_complete_user_func()
   call assert_match('"func Test_cmdline_complete_user', @:)
   call feedkeys(":func s:ScriptL\<Tab>\<Home>\"\<cr>", 'tx')
   call assert_match('"func <SNR>\d\+_ScriptLocalFunction', @:)
+
+  " g: prefix also works
+  call feedkeys(":echo g:Test_cmdline_complete_user_f\<Tab>\<Home>\"\<cr>", 'tx')
+  call assert_match('"echo g:Test_cmdline_complete_user_func', @:)
 endfunc
 
 func Test_cmdline_complete_user_names()

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2341,
 /**/
     2340,
 /**/