bug: documentation older than 7.6.0 is not accessible through the bazel.build version selector

### Page link:

e.g. https://bazel.build/rules/lib/builtins/repository_ctx

### Problem description (include actual vs expected text, if applicable):

bazel.build hosts docs for many more versions of bazel than show up in the version selector on each page - e.g. I found by url manipulation I could get to some docs from bazel 6.5 e.g. https://bazel.build/versions/6.5.0/rules/lib/repository_ctx and 7.5 https://bazel.build/versions/7.5.0/rules/lib/builtins/repository_ctx. However is no obvious way to get to these through the UI.

Ideally there would be a way to switch to older versions, so maybe a select element could hold a much longer list of versions?

### Where do you see this issue? (include link to specific section of the page, if applicable)

basically every page. e.g. https://bazel.build/rules/lib/builtins/Label https://bazel.build/rules/lib/builtins/File and old versions too e.g. https://bazel.build/versions/7.6.0/rules/lib/builtins/LateBoundDefault

### Any other information you'd like to share?

This is especially painful for me because my company is having a hard time keeping up with bazel upgrades - earlier this year we finally made the leap from 6 to 7, and our current version is 7.5.0. So even though we are making progress it seems to be slower than bazel's release of new versions is crowding out the version we're using from the version selector

Start with the version selector on the example bazel.build pages, including /rules/lib/builtins/repository_ctx and /rules/lib/builtins/Label, and compare it with the directly accessible /versions/6.5.0 and /versions/7.5.0 pages. Trace where the selector's version list is defined. Done means older hosted versions such as 6.5.0 and 7.5.0 can be reached through the UI.

Written by the indexing model from the issue text.