Outline links don't respect basePath config

[Victor Oliva]

When using basePath to e.g. deploy to github pages, the outline on the right-hand-side of the page which takes you to different sections of the page has broken links because it doesn't include the basePath.

For example, for a project deployed to https://example.github.io/repoName, the basePath would be set as /repoName.
Then, a page in docs/pages/gettingStarted.mdx has the route https://example.github.io/repoName/gettingStarted, but the links in the outline all take to https://example.github.io/gettingStarted#section

I'll try to raise a PR to address this

[Victor Oliva]

This has been fixed with #144