Rollup merge of #57342 - phansch:make_public, r=Centril
Rollup merge of #57342 - phansch:make_public, r=Centril

librustc_mir: Make qualify_min_const_fn module public

Trying to write a `const_fn` lint for Clippy. @oli-obk suggested
[here][link] to use the `is_min_const_fn` function from the
`qualify_min_const_fn` module. However, the module is currently private
and this commit makes it public.

I lack any historical knowledge of the development of the `const_fn`
feature, so I'm not sure if it was private on purpose or not. fwiw, all
modules are already public except `qualify_min_const_fn`.

r? @oli-obk

[link]: https://github.com/rust-lang/rust-clippy/issues/2440#issuecomment-446109978

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