Auto merge of #5184 - JohnTitor:reduce-dep-size, r=phansch
Auto merge of #5184 - JohnTitor:reduce-dep-size, r=phansch

Reduce `pulldown-cmark` size

Should reduce `pulldown-cmark` size.
ref. https://github.com/raphlinus/pulldown-cmark#build-options

changelog: none

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