broken_link_callback removed support for closures borrowing from their context

[kornelski]

In #484 the change made the callback require 'static lifetime, because Arc has an implicit + 'static bound.

This means that closures which borrow from their environment are forbidden now, and must be made to own all of their state. This is especially difficult to use comrak in methods that take &self and need to call self.some_lookup_method() when fixing links.

The same problem still exists when implementing the BrokenLinkCallback trait, since Arc<dyn BrokenLinkCallback> is always going to require 'static for every implementation.

I suggest changing it to Arc<dyn BrokenLinkCallback + 'c> and restoring the 'c lifetime on options.

[kivikakk]

Hi, thanks for this report! I will loop in @liamwhite here— it seems like we might want to partly revert #484 to permit this.

[kivikakk]

Thank you for the report — this was addressed in #499!