Add suggestion to cast_sign_loss and cast_possible_wrap using the cast_{un,}signed() methods

[RunDevelopment]

changelog: [cast_sign_loss, cast_possible_wrap]: add suggestion using cast_{un,}signed() methods

Fixes #14150

This PR adds a suggestion to cast_sign_loss and cast_possible_wrap, which fixes reported warnings using the cast_{un,}signed() methods, as proposed in #14150. Suggestions are only made if MSRV is >=1.87.

Also, I'm not 100% sure about the suggestion message yet. I'm open for suggestions.

[rustbot]

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[github-actions]

Lintcheck changes for 4e286bb

Lint	Added	Removed	Changed
clippy::cast_possible_wrap	0	0	253
clippy::cast_sign_loss	0	0	294

This comment will be updated if you push new changes

[samueltardieu]

You should also include a test with a MSRV of 1.86 to ensure the suggestions are not emitted.

[RunDevelopment]

I applied all suggestions from the review. Hope this is good now.