patch 8.2.3324: Vim9: Cannot use :silent with :endwhile

Problem:    Vim9: Cannot use :silent with :endwhile.
Solution:   Allow for using the :silent modifier. (closes #8737)
diff --git a/src/proto/ex_docmd.pro b/src/proto/ex_docmd.pro
index f96f8cf..5371439 100644
--- a/src/proto/ex_docmd.pro
+++ b/src/proto/ex_docmd.pro
@@ -10,8 +10,8 @@
 int checkforcmd(char_u **pp, char *cmd, int len);
 int checkforcmd_noparen(char_u **pp, char *cmd, int len);
 int parse_command_modifiers(exarg_T *eap, char **errormsg, cmdmod_T *cmod, int skip_only);
-int has_cmdmod(cmdmod_T *cmod);
-int cmdmod_error(void);
+int has_cmdmod(cmdmod_T *cmod, int ignore_silent);
+int cmdmod_error(int ignore_silent);
 void apply_cmdmod(cmdmod_T *cmod);
 void undo_cmdmod(cmdmod_T *cmod);
 int parse_cmd_address(exarg_T *eap, char **errormsg, int silent);
@@ -32,7 +32,7 @@
 int ends_excmd2(char_u *cmd_start, char_u *cmd);
 char_u *find_nextcmd(char_u *p);
 char_u *check_nextcmd(char_u *p);
-void set_nextcmd(exarg_T *eap, char_u *p);
+void set_nextcmd(exarg_T *eap, char_u *arg);
 char_u *get_command_name(expand_T *xp, int idx);
 void not_exiting(void);
 int before_quit_autocmds(win_T *wp, int quit_all, int forceit);