patch 8.2.1587: loop for handling keys for the command line is too long

Problem:    Loop for handling keys for the command line is too long.
Solution:   Move wild menu handling to separate functions. (Yegappan
            Lakshmanan, closes #6856)
diff --git a/src/proto/cmdexpand.pro b/src/proto/cmdexpand.pro
index 5235659..1c4f954 100644
--- a/src/proto/cmdexpand.pro
+++ b/src/proto/cmdexpand.pro
@@ -9,5 +9,8 @@
 void set_cmd_context(expand_T *xp, char_u *str, int len, int col, int use_ccline);
 int expand_cmdline(expand_T *xp, char_u *str, int col, int *matchcount, char_u ***matches);
 void globpath(char_u *path, char_u *file, garray_T *ga, int expand_options);
+int wildmenu_translate_key(cmdline_info_T *cclp, int key, expand_T *xp, int did_wild_list);
+int wildmenu_process_key(cmdline_info_T *cclp, int key, expand_T *xp);
+void wildmenu_cleanup(cmdline_info_T *cclp);
 void f_getcompletion(typval_T *argvars, typval_T *rettv);
 /* vim: set ft=c : */