Changes the M44 heavy speed loader to be more clear (#7001)

# About the pull request

Changes the M44 heavy speed loader to be more clear on what the round
actually does, since the name "heavy" can be easily mistaken for an AP
round. (imo Marksman and Heavy damage values should be swapped but eh)

# Explain why it's good for the game

Having clear descriptions of what bullets do is good.

# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>

Put screenshots and videos here with an empty line between the
screenshots and the `<details>` tags.

</details>


# Changelog
:cl:
qol: Changes the M44 heavy speed loader description to reflect it's
actual use-case.
/:cl:

code/modules/projectiles/magazines/revolvers.dm

@@ -24,6 +24,7 @@
 
 /obj/item/ammo_magazine/revolver/heavy
 	name = "\improper M44 heavy speed loader (.44)"
+	desc = "A revolver speed loader containing heavy bullets. While less damaging overall than the traditional rounds, they are more accurate."
 	default_ammo = /datum/ammo/bullet/revolver/heavy
 	caliber = ".44"
 	ammo_band_color = REVOLVER_TIP_COLOR_HEAVY