Auto format rendered templates

[ErikSchierboom]

I've been using cljfmt lately and it has been really helpful getting my code formatted nicely. This PR is an experiment to see what happens if we use that library to auto format our generated templates.

The benefits are:

• Consistent style amongst exercises
• Templates become less of a hassle when trying to fix whitespace and do alignment (to me, these have been the most annoying things when building templates)

The main downside is that you would have to adhere to the style used by cljfmt. We could add support to opt-out of auto-formatting, but it would have to be the exception I feel.

[github-actions]

This PR touches files which potentially affect the outcome of the tests of an exercise. This will cause all students' solutions to affected exercises to be re-tested.

If this PR does not affect the result of the test (or, for example, adds an edge case that is not worth rerunning all tests for), please add the following to the merge-commit message which will stops student's tests from re-running. Please copy-paste to avoid typos.

[no important files changed]

For more information, refer to the documentation. If you are unsure whether to add the message or not, please ping @exercism/maintainers-admin in a comment. Thank you!

[ErikSchierboom]

This PR has two commits:

• The actual changes to support auto formatting
• What the changes to the rendered tests look like if they were auto-formatted

[tasxatzial]

Well, this looks perfectly fine to me 👍

[ErikSchierboom]

@tasxatzial I've also included an update to the GENERATORS.md file to document this.