analyze: hypothetical lifetime params aren't added to union defs

[spernsteiner]

pub union Foo {
    x: usize,
    y: *mut u8,
}

struct UseFoo {
    foo: *mut Foo,
}

Rewritten output:

pub union Foo {
    x: usize,
    y: *mut u8,
}

struct UseFoo<'h1,'h0> {
    foo: &'h1 (Foo<'h0>),
}

A lifetime argument is added to the use of Foo in the type of the UseFoo::foo field, but no matching parameter declaration is added to the definition of union Foo.

This might be related to #994.