1. Rename `make_unclosed_delims_error` and return `Vec<Diag>` 2. change magic number `unclosed_delimiter_show_limit` to const 3. move `eof_err` below parsing logic 4. Add `calculate_spacing` for `bump` and `bump_minimal` Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>