Removes the leftover `let _ = level_u8;` and `let _ = header_count;`
discards. The Heading frame already carries the canonical level (we
populated it from `Tag::Heading` at Start), so we destructure that
directly and ignore the redundant `TagEnd::Heading(level)` payload.
The header_count helper was dead — Frame::Table tracks `cols`
internally and we never consumed `header_count`.
altair823
2ac0f56105