We now include the prelude in so many places, this simplifies how we can
present how `cargo-test-support` works.
Yes, this included some `use` clean ups but its already painful enough
walking through every test file, I didn't want to do it twice.
While this is noisy and hides other deprecations, I figured deprecations would
make it easier for people to discover what tasks remain and allow us to
divide and conquer this work rather than doing a heroic PR.
In theory, this will be short lived and we'll go back to seeing
deprecations in our tests.
This allows to use `gitoxide` for all fetch operations, boosting performance
for fetching the `crates.io` index by a factor of 2.2x, while being consistent
on all platforms.
For trying it, nightly builds of `cargo` can specify `-Zgitoxide=fetch`.
It's also possible to set the `__CARGO_USE_GITOXIDE_INSTEAD_OF_GIT2=1` environment
variable (value matters), which is when `-Zgitoxide=none` can be used
to use `git2` instead.
Limitations
-----------
Note that what follows are current shortcomings that will be addressed in future PRs.
- it's likely that authentication around the `ssh` protocol will work differently in practice
as it uses the `ssh` program.
- clones from `file://` based crates indices will need the `git` binary to serve the locatl repository.
- the progress bar shown when fetching doesn't work like the orgiinal, but should already feel 'faster'.
