Pyro Slime Objective Test (#89309)

## About The Pull Request

Pyro Slime is a fairly common role on TG station but many new players
may be unfamiliar to vent crawl or what they need to do, i.e feeding
energy, splitting, this gives a little explainer text to it to make it
easier.
## Why It's Good For The Game

Regular players will know how to play slime well, this gives new players
more of a possible advantage as the role often comes up most rounds as a
ghost role.
## Changelog
🆑
qol: Pyro Slime Objective Text Edit
/🆑

code/modules/antagonists/pyro_slime/pyro_slime.dm

@@ -15,7 +15,7 @@
 	owner.announce_objectives()
 
 /datum/objective/pyro_slime
-	explanation_text = "All I know fire. I speak in tongues of flame. Why is everyone so cold?"
+	explanation_text = "I am fire. I am hunger. The cold is agony. The living pulse with energy; their warmth fuels me. The dead are husks, their embers long faded. Water is death. Fire... fire is freedom."
 
 /datum/objective/pyro_slime/check_completion()
 	return owner.current.stat != DEAD