[skip changelog] Use correct configuration for MkDocs pymdownx.magiclink extension

[per1234]

Please check if the PR fulfills these requirements

• The PR has no duplicates (please search among the Pull Requests before creating one)
• The PR follows our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

• What kind of change does this PR introduce?

Bug fix.

• What is the current behavior?

The pymdownx.magiclink Python-Markdown extension adds support for GitHub-style auto-linked issue/PR/commit/user references in the documentation. In order for the issue/PR/commit references to work correctly in the case where no repository is specified, the extension must be configured with the owner and repository name of the repository that is using it. As a result of not having been updated after it was copied, the extension was previously configured for the squidfunk/mkdocs-material repository, which would result in any references that didn't specify a repository to be relative to that repository, rather than arduino/arduino-cli.

For example, with the previous configuration, this Markdown:

See issue #42 for details.

would result in a link to https://github.com/squidfunk/mkdocs-material/issues/42 rather than the intended #42.

similarly, this Markdown:

The feature was added in e7638c7390fda8bb852688b21014ea392727ea67

would result in a link to https://github.com/squidfunk/mkdocs-material/commit/e7638c7390fda8bb852688b21014ea392727ea67 rather than the intended e7638c7.

• What is the new behavior?

The pymdownx.magiclink extension is correctly configured for use in this repository.

• Does this PR introduce a breaking change?

No.