patch 8.2.4415: function argument name conflicts with C++ keyword

Problem:    Function argument name conflicts with C++ keyword.
Solution:   Rename the argument.
diff --git a/src/proto/usercmd.pro b/src/proto/usercmd.pro
index 8eda5a3..c3ac79c 100644
--- a/src/proto/usercmd.pro
+++ b/src/proto/usercmd.pro
@@ -1,6 +1,6 @@
 /* usercmd.c */
 char_u *find_ucmd(exarg_T *eap, char_u *p, int *full, expand_T *xp, int *complp);
-char_u *set_context_in_user_cmdarg(char_u *cmd, char_u *arg, long argt, int compl, expand_T *xp, int forceit);
+char_u *set_context_in_user_cmdarg(char_u *cmd, char_u *arg, long argt, int context, expand_T *xp, int forceit);
 char_u *set_context_in_user_cmd(expand_T *xp, char_u *arg_in);
 char_u *expand_user_command_name(int idx);
 char_u *get_user_commands(expand_T *xp, int idx);