rustdoc should render the body of assoc tys *before* the where-clause

[fmease]

Given

pub struct S;

pub trait Tr {
    type F<T>
    where
        T: Clone;
}

impl Tr for S {
    type F<T> = T
    where
        T: Clone;
}

rustdoc currently renders the body of the associated type F, namely T, after the where-clause which no longer aligns with the recommended style (see #89122, lint deprecated_where_clause_location):

@rustbot claim
@rustbot label C-bug T-rustdoc A-rustdoc-ui