\S+ was greedily consuming trailing punctuation (. ! , ;) into the URL
match, causing new URL() to mutate clean ASCII URLs — e.g.
"see https://example.com." became "see https://example.com./".
Fix: strip trailing sentence punctuation before parsing, extract and
replace only the hostname (not href) to avoid adding trailing slashes to
bare origins, and restore the stripped tail afterward.
Catriel Müller