The solution is to wrap in explicit link markup `<https://en.wikipedia.org/wiki/...
Test cases: https://en.wikipedia.org/wiki/Sphinx_(documentation_generator) https...
Links ending in parentheses truncate the close-paren: e.g. en.wikipedia.org/wiki/Sphinx_(documentation_generator)
(a copy of) VST is hosted at: https://github.com/vim-scripts/VST
A link to https://github.com/Rykka/riv.vim could also be useful?