Expand the passtune range by 1

Another small quality of life feature. Some players will probably get
peace of mind not having to stand right next to the highly dangerous
drawbridge to activate it.

A few implications, most of which make the Castle slightly easier but
not significantly:
- You no longer have to go in range of the eels/sharks to play the tune.
- You can create a more complex setup to trap monsters and activate it
  from farther out.
- There's a little less risk with accidentally stepping onto the open
  drawbridge right as someone zaps striking at you. (For players who
  don't use paranoid water, it also means less risk of typoing into the
  moat).

doc/xnh-changelog-8.0.md

@@ -42,6 +42,9 @@ changes:
   of it as well, similar to wielding Grayswandir.
 - The Castle drawbridge may fail to close 20% of the time when using the
   passtune.
+- The Castle drawbridge responds to passtune attempts 2 squares away from
+  either of the two drawbridge squares, instead of only directly adjacent
+  squares.
 
 ### Interface changes
 

src/music.c

@@ -750,8 +750,8 @@ do_play_instrument(struct obj* instr)
             exercise(A_WIS, TRUE); /* just for trying */
             if (!strcmp(buf, g.tune)) {
                 /* Search for the drawbridge */
-                for (y = u.uy - 1; y <= u.uy + 1; y++)
-                    for (x = u.ux - 1; x <= u.ux + 1; x++)
+                for (y = u.uy - 2; y <= u.uy + 2; y++)
+                    for (x = u.ux - 2; x <= u.ux + 2; x++)
                         if (isok(x, y))
                             if (find_drawbridge(&x, &y)) {
                                 /* tune now fully known */
@@ -780,8 +780,8 @@ do_play_instrument(struct obj* instr)
                  * we can give the player some hints like in the
                  * Mastermind game */
                 ok = FALSE;
-                for (y = u.uy - 1; y <= u.uy + 1 && !ok; y++)
-                    for (x = u.ux - 1; x <= u.ux + 1 && !ok; x++)
+                for (y = u.uy - 2; y <= u.uy + 2 && !ok; y++)
+                    for (x = u.ux - 2; x <= u.ux + 2 && !ok; x++)
                         if (isok(x, y))
                             if (IS_DRAWBRIDGE(levl[x][y].typ)
                                 || is_drawbridge_wall(x, y) >= 0)