fixes entry for PR #1069

Pull request from vultur-cadens:  writing an unknown spellbook will
succeed if corresponding spell is well known (feasible via divine gift
in 3.7 or object amnesia in earlier versions).  When nearing the point
of fading from memory, Luck is still required but non-wizards only
need the much lower wizard amount.  If already forgotten, the chance
to write the book remains the same as if the spell wasn't known.

Closes #1069

doc/fixes3-7-0.txt

@@ -2188,6 +2188,9 @@ include monster size in feedback for wand of probing and stethoscope
 crystal armor is now subject to cracking damage rather than outright breakage
 when a doppelganger takes on mplayer (fake hero) form, usually choose role
 	from the high scores file; name too if visable at the time
+can now write unknown spellbook without need of Luck when spell is known;
+	if spell becomes known without having read its book (potential divine
+	gift), writing the book while the spell is still fresh will succeed
 
 
 Platform- and/or Interface-Specific New Features