Repaths humans off carbon.

[MistakeNot4892]

Description of changes

• Mass find and replace of /carbon/human to /human.
• Adds comment to electrocute_act()
• Adds map migration for repath.

Why and what will this PR improve

Carbon delenda est.

Authorship

Myself.

Changelog

Nothing player-facing.

[MistakeNot4892]

Please for the love of god merge #3882 before this one, fixing the conflicts from the carbon removal was bad enough.