patch 8.2.2955: Vim9: using filter in compiled command does not work

Problem:    Vim9: using filter in compiled command does not work.
Solution:   Generate EXEC including the command modifier.
diff --git a/src/proto/ex_cmds.pro b/src/proto/ex_cmds.pro
index 1711af4..c083cec 100644
--- a/src/proto/ex_cmds.pro
+++ b/src/proto/ex_cmds.pro
@@ -39,5 +39,6 @@
 void ex_smile(exarg_T *eap);
 void ex_drop(exarg_T *eap);
 char_u *skip_vimgrep_pat(char_u *p, char_u **s, int *flags);
+char_u *skip_vimgrep_pat_ext(char_u *p, char_u **s, int *flags, char_u **nulp, int *cp);
 void ex_oldfiles(exarg_T *eap);
 /* vim: set ft=c : */