Function: get_card_from_link

--Usage--
> get_card_from_link(card: card, "link type")

Inspects a given [[type:card]]'s links to find one of the given type, and returns the linked card.
Returns nil if no card was found.

--Parameters--
! Parameter	Type				Description
| @input@	[[type:string]]		The type of link we want to find.
| @card@	[[type:card]]		The card whose links we'll inspect.
| @set@		[[type:set]]		The set in which to look. This can be omited since 'set' is a predefined variable.