Register 2.1.2

[gafter]

@JuliaRegistrator register()

Fix a macro-expansion-time performance issue.

[JuliaRegistrator]

Registration pull request created: JuliaRegistries/General/119118

Tip: Release Notes

Did you know you can add release notes too? Just add markdown formatted text underneath the comment after the text
"Release notes:" and it will be added to the registry PR, and if TagBot is installed it will also be added to the
release that TagBot creates. i.e.

@JuliaRegistrator register

Release notes:

## Breaking changes

- blah

To add them here just re-invoke and the PR will be updated.

Tagging

After the above pull request is merged, it is recommended that a tag is created on this repository for the registered package version.

This will be done automatically if the Julia TagBot GitHub Action is installed, or can be done manually through the github interface, or via:

git tag -a v2.1.2 -m "<description of version>" 1785df4f3eedfd2d8bc82e4ae920b789cff0634b
git push origin v2.1.2