patch 8.2.4325: 'wildmenu' only shows few matches

Problem:    'wildmenu' only shows few matches.
Solution:   Add the "pum" option: use a popup menu to show the matches.
            (Yegappan Lakshmanan et al., closes #9707)
diff --git a/src/proto/cmdexpand.pro b/src/proto/cmdexpand.pro
index 1c4f954..b64c6bb 100644
--- a/src/proto/cmdexpand.pro
+++ b/src/proto/cmdexpand.pro
@@ -3,6 +3,11 @@
 char_u *ExpandOne(expand_T *xp, char_u *str, char_u *orig, int options, int mode);
 void ExpandInit(expand_T *xp);
 void ExpandCleanup(expand_T *xp);
+void cmdline_pum_display(void);
+int cmdline_pum_active(void);
+void cmdline_pum_remove(void);
+void cmdline_pum_cleanup(cmdline_info_T *cclp);
+int cmdline_compl_startcol(void);
 int showmatches(expand_T *xp, int wildmenu);
 char_u *sm_gettail(char_u *s);
 char_u *addstar(char_u *fname, int len, int context);