Stabilize hydra form duration (tasonir)

Make it a little more consistent.

I considered using random2avg(pow,3), but that wasn't very good
in testing.
Don't place coagulated blood in a vault

Since it's scheduled to be removed in the next major version!
Add a new Depths vault

Hail Snails
Erp (Grunt)
Goliath Beetle tile (Bloax)
Small edits to recent wielded weapon tiles.

Plus the greatsword tile I forgot earlier.
Remove Leda's Liquefication from Hinderance

It's already in three (!) other books, and Hinderance has plenty
else going on, especially with Gell's.
Rename Cigotuvi's Enum (|amethyst)
Remove a useless function argument

The agent parameter in items() has no effect on a stackable item such as
a scroll.
Give Frederick Spellforged Servitor and armour more befitting a demigod

Spellforged Servitor replaces his Invisibility, which isn't terribly
relevant by the time Frederick is encountered. Spellforged enhances
his high-damage spellset in a way that can be countered through
careful positioning.

I also restore his heavier body armour choices so he'll be a bit less
squishy. The justification for the previous downgrade of Frederick's
armour was the lack of realism/player-symmetry from a monster casting
high-level spells in heavy armour. However those issues aren't more
important than giving appropriate defenses to what's supposed to be
one of the hardest uniques in the 3 rune game.
Document a function

Commit 3000 I win.
Completely document a function (reaverb)
Improve items() documentation (makeitem.cc)

[skip ci]
checkwhite
Alphabetize dat/descript/gods.txt
Remove a special Lava Orc line in the Beogh description

Almost all Lava Orcs are gone anyway since there were removed before
hitting stable.
Don't reduce Dispel Undead damage for non-hungry vampires

This wasn’t documented anywhere, was inconsistent with monster vampires,
and probably wouldn’t be impactful even if thoses issue were fixed.
Add some text for Gozag wrath

This should probably be reviewed, but is better than not having any text.

[ci skip]
Make the MP and HP regeneration of !ambrosia independant

Before, the exact number of "points" regenerated (ex. 3 hp/mp) was
shared between the MP and HP regeneration. This was an odd and
unintuitive connection, so now the MP and HP regeneration independently
choose a number between 3-5.