Move clippy::exit into methods

[samueltardieu]

changelog: none

[samueltardieu]

To be merged after #17105

[github-actions]

No changes for 61065ed

[ada4a]

Moving a lint that's explicitly not about methods under methods sounds strange to me...

[samueltardieu]

Moving a lint that's explicitly not about methods under methods sounds strange to me...

methods is badly named and also checks for function calls.

[ada4a]

Should we rename it to calls then maybe?

[samueltardieu]

Either that, or introduce a funcalls module, similar to methods, or move fun calls into the functions module.

But also note that the functions module checks for methods, such as in the misnamed_getters lint.