Move SPWPN_CONFUSE after NUM_REAL_SPECIAL_WEAPONS on next major version bump.

Needed according to SamB on the ##crawl-dev logs.
Add comments about jewellery auto-ID fail, including #1083
Correct a comment
Clarify stash tracker documentation for escaping plusses
Adjust new V monster spawn chances

Vault wardens are more common, especially deeper. Preservers are no
longer oddly frequent on V:5, but appear most often earlier. Convokers
and sentinels are a little more common at shallow depths, and a little
less common on V:5.

Preservers also no longer spawn with orc bands; these were often
fairly pathetic by the time you encountered them together.
Increase vault warden melee damage a little
Reroll shadow creatures which would anger a god, post-generation

In the very small number of cases where a monster has a variable spell set,
and only some of them contain spells opposed by the player's god (chiefly
wizards/ogre magi which have banish in one spell set, but no evil spells
in any others), reroll their spells until a more compatible set is found.

Since this should properly handle any case of monsters which only will
sometimes be angered by the player's god (but not all the time), it should
be safe to reenable the more variable ghost_demons. (Their removal also
had the side-effect of preventing the spell from summoning ugly things or
dancing weapons)
Don't use autoinscriptions for {god gift}.

Having the code add and remove inscriptions is problematic, it's better to
handle these some other way.
Show {god gift} based on the item's origin.

A wee bit simpler than the code removed by the previous commit...
We already did this with artefact properties.
Simplify.
Fix god gift origin being wrong in some cases.

Plain item acquirements had their origin cleared.

Stackable items had the origin set but unused.
A new option, show_god_gift = yes|unindent|no.
Purge stringified {god gift} from old saves.

With a minor tag, so talking about god gifts in inscriptions won't be
affected.
Fix unknown decks being tagged as "identified".

For most uses, decks were special-cased, but fully_identified() is used
at least for search tags, and now also show_god_gift.
Don't crash on shadowy zombies.
Treat spoilery items from uniques the same way as {god gift} (dpeg)
Rework a vault.

I initially expressed hesitation that these monsters belonged in the
main game at all, but at the time it was added there were no objections
and even a bit of encouragement to see them added, when there was
feedback at all (see also #6542, which had absolutely no feedback).

So, now that people are in a situation where they come across it in a
game, they apparently complain endlessly about it without bothering to
inform the vault author that things are in need of a change.

The offending monsters are now gone from the vault. There should be no
problems with it now, right? Right?
Even more vaults!

This batch has two Zot stair vaults, an Abyss rune, an Abyss exit, and
five all-purpose stair minivaults.

There's very little Lua black magic this time around (sorry if there are
any folks hoping for that!) - just straight-up monster battles for the
most part.
Discard empty boxes of beasts after use.
Use regular plants, bushes and fungi in a vault.

Redefines there serve no purpose, and make things really hard to see,
which causes problems because of oklobs which share the glyph.