add a master off/on switch for sounds

sounds can be set in the config file or on the fly with the Options menu.

This also adds a mechanism for specifying a terminology preference
for a boolean option in the options menu.

The choices are: Term_False, Term_Off, Term_Disabled

Term_False, the default, will use the terms "false" and "true" in the
Options menu.
Term_Off will use the terms "off" and "on" in the Options menu.
Term_Disabled will use the terms "disabled" and "enabled" in the Options
menu.

I didn't review any of the existing options to see if one of the new
alternative terms might be a better fit. They were all left at the default.

doc/Guidebook.mn

@@ -37,7 +37,7 @@
 .ds f0 "\*(vr
 .ds f1
 .\"DO NOT REMOVE NH_DATESUB .ds f2 "DATE(%B %-d, %Y)
-.ds f2 "December 28, 2022
+.ds f2 "January 30, 2023
 .
 .\" A note on some special characters:
 .\" \(lq = left double quote
@@ -4483,6 +4483,8 @@ order by count, low to high; ties broken by internal index.
 .PE
 Can be interactively set via the \(oq\f(CRm O\fP\(cq command or via using
 the \(oq\f(CRm\fP\(cq prefix before the #vanquished command.
+.lp "sounds "
+Allow sounds to be emitted from an integrated sound library (default on).
 .lp "sparkle "
 Display a sparkly effect when a monster (including yourself) is hit by an
 attack to which it is resistant (default on).