Rollup merge of #107486 - compiler-errors:bound-ty-keep-name, r=oli-obk

Track bound types like bound regions

When we instantiate bound types into placeholder types, we throw away the names for some reason. These names are particularly useful for error reporting once we have `for<T>` binders.

r? types

diff --cc compiler/rustc_middle/src/ty/print/pretty.rs
Simple merge