patch 8.2.2603: Vim9: no effect if user command is also a function

Problem:    Vim9: no effect if user command is also a function.
Solution:   Check for paren following. (closes #7960)
diff --git a/src/proto/evalvars.pro b/src/proto/evalvars.pro
index 1094d45..c75f80a 100644
--- a/src/proto/evalvars.pro
+++ b/src/proto/evalvars.pro
@@ -61,7 +61,7 @@
 dictitem_T *find_var(char_u *name, hashtab_T **htp, int no_autoload);
 dictitem_T *find_var_in_ht(hashtab_T *ht, int htname, char_u *varname, int no_autoload);
 hashtab_T *get_script_local_ht(void);
-int lookup_scriptitem(char_u *name, size_t len, cctx_T *dummy);
+int lookup_scriptitem(char_u *name, size_t len, int cmd, cctx_T *dummy);
 hashtab_T *find_var_ht(char_u *name, char_u **varname);
 char_u *get_var_value(char_u *name);
 void new_script_vars(scid_T id);
diff --git a/src/proto/ex_docmd.pro b/src/proto/ex_docmd.pro
index dcd9f39..9ac8eaf 100644
--- a/src/proto/ex_docmd.pro
+++ b/src/proto/ex_docmd.pro
@@ -13,7 +13,7 @@
 int parse_cmd_address(exarg_T *eap, char **errormsg, int silent);
 int checkforcmd(char_u **pp, char *cmd, int len);
 char_u *skip_option_env_lead(char_u *start);
-char_u *find_ex_command(exarg_T *eap, int *full, int (*lookup)(char_u *, size_t, cctx_T *), cctx_T *cctx);
+char_u *find_ex_command(exarg_T *eap, int *full, int (*lookup)(char_u *, size_t, int cmd, cctx_T *), cctx_T *cctx);
 int modifier_len(char_u *cmd);
 int cmd_exists(char_u *name);
 void f_fullcommand(typval_T *argvars, typval_T *rettv);