When an URL in a documentation comment is broken across multiple lines `rustdoc` won't link it properly. We should lint about these. <!-- TRIAGEBOT_START --> <!-- TRIAGEBOT_ASSIGN_START --> <!-- TRIAGEBOT_ASSIGN_DATA_START$${"user":"maxcnunes"}$$TRIAGEBOT_ASSIGN_DATA_END --> <!-- TRIAGEBOT_ASSIGN_END --> <!-- TRIAGEBOT_END -->