This ignores 2.x.1 (etc) releases, which prevents it from thinking
the next official non-point-release version is 2.26.1, when it
should be 2.26.0, because it saw the "latest" release is 2.24.1.
This fixes the wiki ending up with imaginary version numbers for
the "this function is available since SDL 2.x.y" sections.
Fixes#6343.
This keep documentation future-accurate and more importantly: it will
produce correct results before we tag the official release in git, so
they'll be correct in the tag and the release tarball.
This will let us automate this so it's managed for us, and as things go
from development to official releases, the documentation will automatically
update!
Ryan C. Gordon