Option to create the character deaf

Allows creating your character permanently deaf,
for that added challenge.

Breaks saves.

doc/Guidebook.tex

@@ -3635,6 +3635,8 @@ Reached the Elemental Planes.
 Reached the Astral Plane level.
 \item[{\tt Blind}]
 Blind from birth.
+\item[{\tt Deaf}]
+Deaf from birth.
 \item[{\tt Nudist}]
 Never wore any armor.
 \item[{\tt Ascended}]
@@ -3683,10 +3685,10 @@ enough---but not too close!---to
 the Castle level's drawbridge or can be given to you via prayer boon.
 
 %.pg
-{\it Blind\/} and {\it Nudist\/} are also conducts, and they can only be
+{\it Blind\/}, {\it Deaf\/}, and {\it Nudist\/} are also conducts, and they can only be
 enabled by setting the correspondingly named option in {\tt NETHACKOPTIONS}
 or run-time configuration file prior to game start.
-In the case of {\it Blind\/}, the option also enforces the conduct.
+In the case of {\it Blind\/} and {\it Deaf\/}, the option also enforces the conduct.
 They aren't really significant accomplishments unless/until you make
 substantial progress into the dungeon.
 
@@ -4161,6 +4163,9 @@ peaceable creatures (default on).  Persistent.
 \item[\ib{dark\verb+_+room}]
 Show out-of-sight areas of lit rooms (default on).  Persistent.
 %.lp
+\item[\ib{deaf}]
+Start the character permanently deaf (default false).  Persistent.
+%.lp
 \item[\ib{disclose}]
 Controls what information the program reveals when the game ends.
 Value is a space separated list of prompting/category pairs