Name all three forms git describe gives for the version

README, script/version and the version test's header said git describe
gives the tag or the short commit. On a commit after a tag it gives the
tag, the commits since it and the short commit; each place now names
that case too.

Model: opus-5-5

README.md

@@ -189,7 +189,8 @@ places, and reads `.gitignore` as its default ignore file — which is why
 - the `VERSION` environment variable, or the `Dockerfile`'s `VERSION` build arg
   (`--build-arg VERSION=...`), when one is given and not empty;
 - otherwise, in a checkout with `.git`, `git describe --tags --always`: the tag
-  on a tagged commit, otherwise the short commit;
+  on a tagged commit; the tag, the commits since it and the short commit on a
+  later commit (`v1.2.3-4-gabc1234`); the short commit when no tag is reachable;
 - otherwise, as in a source tarball, the version `package.json` declares.
 
 The build fails if the checkout has `.git` and the version still comes out