.github: add a link to Release Notes Language Style Guide in PR template (#32745)
.github: add a link to Release Notes Language Style Guide in PR template (#32745)

close pingcap/tidb#32746
kyle-wang/tidb,kyle-wang/tidb,kyle-wang/tidb,ngaut/tidb,ngaut/tidb,c4pt0r/tidb,c4pt0r/tidb,ngaut/tidb,pingcap/tidb,c4pt0r/tidb,ngaut/tidb,c4pt0r/tidb,pingcap/tidb,kyle-wang/tidb,pingcap/tidb,ngaut/tidb,pingcap/tidb,pingcap/tidb,pingcap/tidb,kyle-wang/tidb,ngaut/tidb,kyle-wang/tidb,c4pt0r/tidb,c4pt0r/tidb