code maintenance bit to white-list current "You hear" instances

Flag existing occurrences of "You hear" as "Deaf-aware" so
that a grep for that string in the future doesn't need to
trigger further investigation of those.

src/shk.c

@@ -2990,7 +2990,7 @@ boolean peaceful, silent;
                 Norep("%s booms: \"%s, you are a thief!\"",
                       Shknam(shkp), plname);
             } else if (!Deaf) {
-                Norep("You hear a scream, \"Thief!\"");
+                Norep("You hear a scream, \"Thief!\"");  /* Deaf-aware */
             }
         }
         hot_pursuit(shkp);