enh: harvest URLs from Hypothes.is comments & higleted text

[ankostis]

... plus a minor simplification-refactoring.

[karlicoss]

Good idea, thanks!

[ankostis]

I usually try to keep these helpers below 'index'

I follow call-dependency order, so that contradicted with the UX-order you follow - will keep that in mind next time, and put exclusively index() at the top, ok?

if there are multiple arguments of same type (like text/part_name), I usually force them to be keyword

I would rewrite this PR to inline the helper-function, and eliminate both nits, but now its been merged ¯\_(ツ)_/¯

[karlicoss]

ill keep that in mind next time

Thanks! No problem anyway, it makes sense too! Like I said more of a nit.

I would rewrite this PR to inline the helper-function, and eliminate both nits, but now its been merged

IMO it's better to merge sooner than later for faster iteration if it doesn't break things :) But I can ask first next time if you prefer?