CLI: Show source context by default in `ruff check`

[zanieb]

The --show-source flag can be used to show source information alongside violations during ruff check. This should be the default behavior.

--no-show-source can be used to return to the previous output. In the future, this option will be removed; see #7350.

[MichaReiser]

How does this align with our long-term goal of removing --show-source in favor of different formats?

[charliermarsh]

This is already the case in preview, right?

[zanieb]

Yeah I believe this was completed in #9687

Should we leave the issue open to track making it the non-preview default?

[T-256]

IIUC --output-fomat=full as default is stabilized in v0.5, why keeping this issue for v0.6 milestone?