rustdoc should show module for types when the type name is not unique

[quodlibetor]

If you look at the docs for ExactSizeIterator there are I think literally hundreds of implementations, with perhaps dozens that look identical, e.g. here are some lines I copied out:

impl<'a, T> ExactSizeIterator for Iter<'a, T>
impl<T> ExactSizeIterator for IntoIter<T>
impl<'a, T> ExactSizeIterator for Iter<'a, T>
impl<'a, T> ExactSizeIterator for IterMut<'a, T>
impl<T> ExactSizeIterator for IntoIter<T>
impl<T> ExactSizeIterator for IntoIter<T>

Those are all distinct implementations, but with the idiom of not-stuttering module names in type-names it is impossible to know which type you're looking for without hovering your mouse over each.

Those lines would be more helpful if they looked like:

impl<'a, T> ExactSizeIterator for btree_set::Iter<'a, T>
impl<T> ExactSizeIterator for btree_set::IntoIter<T>
impl<'a, T> ExactSizeIterator for linked_list::Iter<'a, T>
impl<'a, T> ExactSizeIterator for linked_list::IterMut<'a, T>
impl<T> ExactSizeIterator for linked_list::IntoIter<T>
impl<T> ExactSizeIterator for vec::IntoIter<T>

IMO the way that rustdoc should handle this is it should check if the type is ambiguous at all in the current documentation run (not just ambiguous on the current documentation page) and disambiguate with as many modules as necessary.