newbie in-game assistance with Guidebook notation

Provide some command assistance for newbies, but
suppress it with !cmdassist in the config file.

If someone misinterprets the Guidebook ^D, ^T
type command notation, this will pop up some
further information to possibly assist them and
explain the notation.

include/extern.h

@@ -1369,6 +1369,7 @@ E int NDECL(dowhatis);
 E int NDECL(doquickwhatis);
 E int NDECL(doidtrap);
 E int NDECL(dowhatdoes);
+E char *FDECL(dowhatdoes_core,(CHAR_P, char *));
 E int NDECL(dohelp);
 E int NDECL(dohistory);
 

include/flag.h

@@ -254,6 +254,7 @@ struct instance_flags {
 	boolean wc_eight_bit_input;	/* allow eight bit input               */
 	boolean wc_mouse_support;	/* allow mouse support */
 
+	boolean  cmdassist;	/* provide detailed assistance for some commands */
 	/* Items which belong in flags, but are here to allow save compatibility */
 	boolean  lootabc;	/* use "a/b/c" rather than "o/i/b" when looting */
 	boolean  showrace;	/* show hero glyph by race rather than by role */