Add vision sanity checking, fix more vision

- Add a vision sanity checking routine

- Recalc block point when digging a door for temporary clouds

- Add recalc_block_point after cvt_sdoor_to_door, because doorways
  on the Rogue level have no doors, and otherwise the sanity checking
  would complain.  This doesn't actually change how the Rogue level
  vision works, as it uses a different vision system

- Monster using a trap in a secret corridor revealed the corridor,
  but didn't unblock the vision unless you saw the location

src/zap.c

@@ -3707,6 +3707,7 @@ zap_map(
         /* secret door gets revealed, converted into regular door */
         if (ltyp == SDOOR) {
             cvt_sdoor_to_door(&levl[x][y]); /* .typ = DOOR */
+            recalc_block_point(x, y);
             newsym(x, y);
             if (cansee(x, y)) {
                 pline("Probing reveals a secret door.");
@@ -5331,6 +5332,7 @@ zap_over_floor(
     /* secret door gets revealed, converted into regular door */
     if (levl[x][y].typ == SDOOR) {
         cvt_sdoor_to_door(&levl[x][y]); /* .typ = DOOR */
+        recalc_block_point(x, y);
         /* target spot will now pass closed_door() test below
            (except on rogue level) */
         newsym(x, y);