Auto merge of #4211 - flip1995:check_changelog, r=matthiaskrgr
Auto merge of #4211 - flip1995:check_changelog, r=matthiaskrgr

Check for changelog entry in PR bodies

cc #4031 but now on the auto and try branches. (https://github.com/rust-lang/rust-clippy/issues/3955#issuecomment-502230021)

changelog: none

aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust