update code comment style (#8325)
update code comment style (#8325)

Signed-off-by: Calvin Weng <03310b1688af3ac6d84b03af03b0c4d581e884d9@pingcap.com>

Co-authored-by: winkyao <3b244066520a860fbb7b58c30f76d89587554bd4@gmail.com>
BusyJay/tikv,pingcap/tikv,BusyJay/tikv,c4pt0r/tikv,BusyJay/tikv,BusyJay/tikv,pingcap/tikv