pp: typo in comment
pp: also print bounds in paths with no generic params

Since 3b6314c3 the pretty printer seems to only print trait bounds for
`ast::ty_path(...)`s that have a generics arguments list. That seems
wrong, so let's always print them.

Closes #9253, un-xfails test for #7673.
auto merge of #9264 : ben0x539/rust/pp-work, r=alexcrichton

Since 3b6314c the pretty printer seems to only print trait bounds for `ast::ty_path(...)`s that have a generics arguments list. That seems wrong, so let's always print them.

Closes #9253, un-xfails test for #7673.