Rollup merge of #143848 - makai410:smir-rename, r=oli-obk

Rename `stable_mir` and `rustc_smir`

This PR only renames the two crate names.

There is no doubt that we want to rename `stable_mir` to `rustc_public`, while it hasn't been discussed yet that what the new name for `rustc_smir` should be.

This PR proposes a new name for `rustc_smir`, that is `rustc_public_shim`, since `rustc_smir` now is mostly a proxy to do calls to rustc queries and the public API of rustc that is invoked by the `rustc_public` crate.

However, I don't think that name is good enough. I hope there would be a way better name.

r? `@oli-obk`

Author: samueltardieu