Get last names from BibTeX-formatted author string fullnames

Replace all sequences of whitespace in s with a single space

Join a collection of (last-)names as they would naturally be formatted.
[A]         ->   A
[A, B]      ->   A and B
[A, B, C]   ->   A, B and C (no Oxford comma)

Contruct a new map with all the values of the map kvs passed through f

NFC-normalize the string s

Escape any regular expression syntax characters in s such that the result can be
embedded in a regular expression, but will only match literally equivalent strings.

Parse the string fullname into a vector of [given-names surname],
or just [given-names] if no surname is given.