Auto merge of #60318 - jethrogb:jb/try-from-slice-to-infallible, r=sfackler
Auto merge of #60318 - jethrogb:jb/try-from-slice-to-infallible, r=sfackler

impl From<Infallible> for TryFromSliceError

I believe this was missed when TryFrom was stabilized. I think `TryFromSliceError` and `TryFromIntError` are the only two `TryFrom` error types that appear in `std`. I think trait implementations have to be insta-stable, but I'm not sure.

graydon/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust