Higher chance of demon gating in Gehennom

doc/fixes3-7-0.txt

@@ -1090,6 +1090,7 @@ allow setting per-level "temperature": hot, cold, or temperate, currently
 digging is noisy
 polymorphing into fire elemental allows you eat flammable items
 hitting sleeping monsters will cause them to wake up noisily
+demon gating happens more in Gehennom and less outside it
 
 
 Fixes to 3.7.0-x Problems that Were Exposed Via git Repository

src/mhitu.c

@@ -845,7 +845,7 @@ summonmu(struct monst *mtmp, boolean youseeit)
 
     if (is_demon(mdat)) {
         if (mdat != &mons[PM_BALROG] && mdat != &mons[PM_AMOROUS_DEMON]) {
-            if (!rn2(13))
+            if (!rn2(Inhell ? 10 : 16))
                 (void) msummon(mtmp);
         }
         return; /* no such thing as a demon were creature, so we're done */