3927: Use correct URL for past versions documentation

[krzywon]

Description

This updates the URLs used for past version of our documentation. This also updates the help tests to use an older version so future developers don't expect they need to update this version for every release.

One question: Should get_current_release_version() be in sas.system.web, where I have it now, or would it make more sense to be in sas.system.version?

Fixes #3927

How Has This Been Tested?

Units tests pass

Review Checklist:

Documentation (check at least one)

• There is nothing that needs documenting
• Documentation changes are in this PR
• There is an issue open for the documentation (link?)

Installers

• There is a chance this will affect the installers, if so
  • Windows installer (GH artifact) has been tested (installed and worked)
  • MacOSX installer (GH artifact) has been tested (installed and worked)
  • Wheels installer (GH artifact) has been tested (installed and worked)

Licensing (untick if necessary)

• The introduced changes comply with SasView license (BSD 3-Clause)

[krzywon]

This is already being worked on by @rozyczko in #3926. Sorry!

[DrPaulSharp]

I'll hold fire on the review then.

[krzywon]

@rozyczko - could you compare this PR to your own in #3926 and let me know what I should do with this, when you have a moment, please?

[pkienzle]

I noticed that the constructed URL to old docs contains // in the path: https://www.sasview.org/docs/old_docs/6.1.2//index.html

Anyway, wouldn't it be better to handle a redirect from docs/index.html to docs/v{current_version}/index.html on the server so that sasview installations out in the wild with the existing path don't break?

[krzywon]

Anyway, wouldn't it be better to handle a redirect from docs/index.html to docs/v{current_version}/index.html on the server so that sasview installations out in the wild with the existing path don't break?

The feature @rozyczko and I are trying to fix was introduced after v6.1.3. The URL in question has only seen the 2 most recent alpha releases, so now is the time to fix this.

[pkienzle]

Okay.

FWIW, I like the initial choice of url as docs/v{version} better than docs/old_docs/{version}. That way you never have to query the web to see what is the most recent version.