Lots of description changes and grammar fixes for heretics (#81761)

## About The Pull Request

Changes a lot of text. Apart from grammar fixes, here are the notable
changes:

- Ash jaunt description just said it is a "short range jaunt" without
explaining what exactly a jaunt is. I believe it is better to describe
without comparing to another spell the player may not have experience
with.
- Cosmic grasp now explains what the deal is with star marks and cosmic
fields. It is still possible to crosspath into a star mark spell,
skipping this description, but I assume a player like that is
experienced enough to know what the star mark does anyway...
- The knowledge for ash spirits no longer refers to them as "Ash Men" -
"Ash Spirit" is the mob's actual name. If you think "Ash Man" is a
better name, I can change it around so that the mob gets renamed that
instead.
- Removes the lines from paradoxical curio's description about causing
brain damage on examination - many heretic items cause adverse effects
to heathens who try to interact with them, and there is never a need to
clutter the description with them.
- Changes the eldritch coin description, because the old one was, in my
opinion, awkward. I changed it to be more inline with the other items'
descriptions, and to not tell non-heretics what its purpose is. If you
liked the old one better, I can revert this change.
## Why It's Good For The Game

Grammar good. Accurate descriptions good.
## Changelog
🆑
fix: made some heretic descriptions more accurate
spellcheck: improved english of the heretical eldritch patrons
/🆑

code/datums/brain_damage/severe.dm

@@ -419,7 +419,7 @@
 	desc = "Patient seems to oxidise things around them at random, and seem to believe they are aiding a creature in climbing a mountin."
 	scan_desc = "C_)L(#_I_##M;B"
 	gain_text = span_warning("The rusted climb shall finish at the peak")
-	lose_text = span_notice("The rusted climb? Whats that? An odd dream to be sure.")
+	lose_text = span_notice("The rusted climb? What's that? An odd dream to be sure.")
 	random_gain = FALSE
 
 /datum/brain_trauma/severe/rusting/on_life(seconds_per_tick, times_fired)