patch 8.2.3731: "set! termcap" shows codes in one column, but not keys

Problem:    "set! termcap" shows codes in one column, but not keys.
Solution:   Also use one column for keys. (closes #9258)
diff --git a/src/proto/term.pro b/src/proto/term.pro
index 949b350..6f0f081 100644
--- a/src/proto/term.pro
+++ b/src/proto/term.pro
@@ -80,7 +80,7 @@
 void term_get_fg_color(char_u *r, char_u *g, char_u *b);
 void term_get_bg_color(char_u *r, char_u *g, char_u *b);
 char_u *replace_termcodes(char_u *from, char_u **bufp, int flags, int *did_simplify);
-void show_termcodes(void);
+void show_termcodes(int flags);
 int show_one_termcode(char_u *name, char_u *code, int printit);
 void update_tcap(int attr);
 void swap_tcap(void);