This ports our example testing over to [trycmd](https://docs.rs/) so
we can:
- More thoroughly test our examples
- Provide always-up-to-date example usage
The old way of testing automatically picked up examples. This new way
requires we have a `.md` file that uses the example in some way.
Notes:
- Moved overall example description to the `.md` file
- I added cross-linking between related examples
- `14_groups` had a redundant paragraph (twice talked about "one and
only one"
This reverts commit 6898fbde33.
PR #2144 added the `license` field but no consumer has been added since
the (like Issue #1768). Since this is not ready yet, I am pulling it
from the 3.0 release.
So far, our main route for pulling a feature from the release has
been to put it behind a `unstable-*` feature flag and to create a
stablization tracking issue. I chose to instead remove the feature
because a write-only field with no effect does not provide values for
people to use in as an early access and so doesn't outweight the cost of
the extra documentation noise and code noise it creates. Additionally,
keeping an `unstable-` feature around when it has such an unknown path
(and time table) to stalbization feels like it violates YAGNI. I'm
uncertain how much of this feature we can implement and not create a
legal trap for users because the crate's license is insufficient for the
final artifact's license. I feel our stabliazation process sshould be
about iteration and collecting user feedback which this doesn't line up
with.
When someone is ready to tackle #1768, it will be easy to revert this
commit and pick up the work again.
Fixes#3001
