Export xml_nodes_to_lint()?

[AshesITR]

Used in most linters by now, because it's a very useful helper for XPath-based linting.
Since we already export with_id and ids_with_token as helpers for the parse data based approach, I think we could also export xml_nodes_to_lint().

Also thinking about the function name: Shouldn't this be either vectorized (on nodesets or lists of nodes) or singular (xml_node_to_lint())?

cc @MichaelChirico

[MichaelChirico]

SGTM-- had the same thought about vectorizing.

(PS I just moved so it will take me a bit to get things in order and get back to he review/PR queue)

[MichaelChirico]

Assigning this to me -- I have a branch in progress already