Track maintainers found that they wanted to add comments to the tests.toml file to e.g. indicate _why_ a test was not included.
Unfortunately, running configlet sync would re-generate the entire file so any manually added comments were lost.
In this commit we're updating the format of tests.toml files to support adding comments.
We do this by creating a separate table for each test case which has `description` and `include` fields.
Tracks are then free to add additional fields, like a `comment` field, but also anything they feel might be useful to them.
For more information, see this discussion: https://github.com/exercism/configlet/issues/186