Even more let_else adoptions

[est31]

Continuation of #89933, #91018, #91481, #93046, #93590.

[rust-highfive]

r? @lcnr

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[est31]

In the wake of #93951 I wanted to increase the amount let else is tested in the compiler, so I wrote a clippy lint to identify even more places that could benefit from using let else. I didn't find any issues with the let else feature, although I found some false positives for my lint, so this exercise was helpful :).

[lcnr]

1 nit, after that r=me

[joshtriplett]

@bors r=lcnr

[bors]

📌 Commit 60f969a has been approved by lcnr