Add some comments to `mir::Static` and `mir::StaticKind`
Add some comments to `mir::Static` and `mir::StaticKind`

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