Improve rustdoc strippers #138168
Description
Currently, rustdoc goes through multiple passes to inline reexports, remove hidden/private items.
First, we go through the whole crate AST, to convert types into rustdoc types (although the rustdoc types are now more and more just wrapper around rustc types), then we run these passes. However: couldn't we do the stripping as part of this conversion?
It could also potentially help with performance in cases like #137534.