vim-patch:8.2.4325: 'wildmenu' only shows few matches (#19876)

Problem:    'wildmenu' only shows few matches.
Solution:   Add the "pum" option: use a popup menu to show the matches.
            (Yegappan Lakshmanan et al., closes vim/vim#9707)
3908ef5017

Omit p_wmnu check in cmdline_pum_active() as it can cause problems.
Omit vim_strchr() flags as that isn't really better than bitmasks.
Omit key translations and document it in vim_diff.txt.

src/nvim/ex_getln.c

@@ -1801,6 +1801,10 @@ static int command_line_handle_key(CommandLineState *s)
     if (nextwild(&s->xpc, WILD_ALL, 0, s->firstc != '@') == FAIL) {
       break;
     }
+    if (cmdline_pum_active()) {
+      cmdline_pum_cleanup(&ccline);
+      s->xpc.xp_context = EXPAND_NOTHING;
+    }
     return command_line_changed(s);
 
   case Ctrl_L: