fix a typo in the SQL example for troubleshoot-write-conflicts.md (#7485)
fix a typo in the SQL example for troubleshoot-write-conflicts.md (#7485)

* tidb-configuration-file: add unit for log.max-size

* fix default value of log.max-size

* Update tidb-configuration-file.md

* fix a typo in the SQL example

Co-authored-by: TomShawn <3d0966147538bc5ab020e8dffa2c0b746f9728a6@users.noreply.github.com>
pingcap/docs-cn,pingcap/docs-cn