patch 8.2.1898: command modifier parsing always uses global cmdmod

Problem:    Command modifier parsing always uses global cmdmod.
Solution:   Pass in cmdmod_T to use.  Rename struct fields consistently.
diff --git a/src/proto/ex_docmd.pro b/src/proto/ex_docmd.pro
index 32fada5..f8cb7ef 100644
--- a/src/proto/ex_docmd.pro
+++ b/src/proto/ex_docmd.pro
@@ -6,9 +6,9 @@
 void *getline_cookie(char_u *(*fgetline)(int, void *, int, getline_opt_T), void *cookie);
 char_u *getline_peek(char_u *(*fgetline)(int, void *, int, getline_opt_T), void *cookie);
 char *ex_errmsg(char *msg, char_u *arg);
-int parse_command_modifiers(exarg_T *eap, char **errormsg, int skip_only);
+int parse_command_modifiers(exarg_T *eap, char **errormsg, cmdmod_T *cmod, int skip_only);
 void apply_cmdmod(cmdmod_T *cmod);
-void undo_cmdmod(int save_msg_scroll);
+void undo_cmdmod(cmdmod_T *cmod);
 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);