Rollup merge of rust-lang#102820 - ehuss:let-else-nightly-suggestion,…

… r=petrochenkov

Show let-else suggestion on stable.

The E0005 error message has a suggestion to use let-else. Now that let-else is stabilized, I think this message should be included on non-nightly toolchains. I suspect this was just an oversight from rust-lang#93628.  [`E0005.stderr`](https://github.com/ehuss/rust/blob/be1c7aad723126b2ea65543b4ceed54167b841a2/src/test/ui/error-codes/E0005.stderr#L22-L25) contains an example of what this suggestion looks like.