chore: clarify how to write good pull request titles (#6685)
chore: clarify how to write good pull request titles (#6685)

Co-authored-by: Kanit Wongsuphasawat <dc2a36cfe81552efa95c0328cefeed21c9a757cc@gmail.com>
vega/vega-lite,vega/vega-lite,uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite,vega/vega-lite