Stabilize assert_matches

[luqmana]

Closes #82775

@rustbot modify labels: +T-libs-api

[rust-highfive]

r? @kennytm

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[luqmana]

#82775 was approved in Jan so I figured I'd open this to get things going.

There was some confusion about whether or not we'd stabilize it in its current path (std::assert_matches::assert_matches). As far as I can tell that is the plan and it'll be considered for adding to the prelude in the next edition.

[luqmana]

r? @m-ou-se

[m-ou-se]

This PR is stabilizing this macro as std::assert_matches::assert_matches!() rather than std::assert_matches!(). The assert_matches module was just a temporary hack to fix some breakage. This problem hasn't been resolved yet on the tracking issue (#82775).

[luqmana]

Ah,

This PR is stabilizing this macro as std::assert_matches::assert_matches!() rather than std::assert_matches!(). The assert_matches module was just a temporary hack to fix some breakage. This problem hasn't been resolved yet on the tracking issue (#82775).

Ah, I thought I saw a comment about a T-libs meeting deciding on the module approach for now but looks like there wasn't final consensus there. I'll close this for now thanks.