(MAINT) Update URLs for site rebrand

[sdwheeler]

PR Summary

The docs site has been rebranded. The URL changed from docs.microsoft.com to learn.microsoft.com. URLs pointing to docs.microsoft.com are redirected but the need to be updated to avoid the redirection.

This PR updates the URLs to point to the new hostname.

PR Checklist

• [x] PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• [x] Summarized changes
• [x] Change is not breaking
• [ ] Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
• [ ] Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
• [x] This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.

[sdwheeler]

See related PR https://github.com/MicrosoftDocs/PowerShell-Docs-Modules/pull/103

[bergmeister]

See related PR MicrosoftDocs/PowerShell-Docs-Modules#103

I do not see the same changes to the markdown files in the Rules folder that are in this PR.

[sdwheeler]

I do not see the same changes to the markdown files in the Rules folder that are in this PR.

That's because the Docs repo uses site-relative links that omit the hostname portion of the URL. We can switch to site-relative links in the source code repo but that means that the URLs don't work when viewed from GitHub. Are there Pester tests for links? If not then it would be safe to switch to site-relative links in the source and make publishing the docs easier at release time.

[sdwheeler]

I just pushed a new commit to restore full URLs in the source files that had been converted to site-relative.

I remember now from discussions with Jim, we want to use full URLs in the source because the source docs for a tagged release need to have working URLs. We need to convert them links to site-relative when the files are copied to the docs repository.

[bergmeister]

@sdwheeler When I updated my other MSDocs PR with this, I found that the below change was not synced back to PSSA repo: https://github.com/MicrosoftDocs/PowerShell-Docs-Modules/commit/747cff56148e7f8b04df3ca5bb5faeb42590ac7b#diff-7f36cb7cb779ee3d32ec0749bba06c5a5fbd5398106c748acf80fee400ce7115