throw-and-return for aklys

The comment I added to data.base--to explain that despite what the
short description says, an aklys wouldn't return to sender after being
thrown--was bugging me, so I've made aklyses behave like Mjollnir.
If thrown when wielded as primary weapon, it will usually return and
usually be re-wielded.  I also added a new message when either thrown
Mjollnir or thrown aklys is expected to return and fails to do so.

Most of the diff to dothrow.c is a change in indentation level.  The
amount of code needed was quite small.

Autopickup for thrown Mjollnir which had failed to return was putting
it into the quiver slot if that was empty.  Note quite an outright bug,
but it started wielded and can't be thrown if quivered, so exclude it
from the stuff that will auto-fill the quiver slot when added to invent
(post-3.6.0 issue).

doc/fixes36.1

@@ -595,6 +595,8 @@ unix: fix for freeing MAIL also introduced a memory leak whenever new mail
 when clairvoyance lets you move the cursor to examine the map (if it occurs
 	when engulfed or underwater or when blessed clairvoyance finds a
 	monster), the "for instructions type '?'" prompt could be confusing
+prevent Mjollnir from being auto-quivered if it's been thrown without return
+	and then picked back up while quiver slot is empty
 
 
 Platform- and/or Interface-Specific Fixes
@@ -785,6 +787,9 @@ change #adjust's behavior when collecting compatible stacks; that used to
 a prayer result which results in uncursing some or all of the hero's items
 	won't uncurse a worn helm of opposite alignment since that would
 	facilitate the hero switching to another god by taking it off
+wielded aklys behaves like Mjollnir when thrown--it usually returns; unlike
+	Mjollnir, it isn't limited to Valkyries or need gauntlets of power
+	(so far, hero-only; an aklys won't return if thrown by a monster)
 
 
 Platform- and/or Interface-Specific New Features