K&R commands: 2 x missing forward declaration removal

Functions do not appear to exist:
 extern void DisplayWindow();
 extern void DisplayWindow();

K&R obsolete syntax removal for C23 compatibility series

commands/CmdRS.c

@@ -62,8 +62,6 @@ static char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magic-8.0/
 #include "router/router.h"
 #include "wiring/wiring.h"
 
-extern void DisplayWindow();
-
 /* Used by CmdSetLabel() */
 Label *DefaultLabel;
 

commands/CmdTZ.c

@@ -57,8 +57,6 @@ static char rcsid[] __attribute__ ((unused)) = "$Header: /usr/cvsroot/magic-8.0/
 #include "yacr.h"
 #endif	/* LLNL */
 
-extern void DisplayWindow();
-
 /* Trivial function that returns 1 if called */
 
 int