Mention spec and indented blocks in doctest docs
Mention spec and indented blocks in doctest docs

This commit adds a new section to the Documentation Test docs, which briefly mentions indented code blocks, and links to the CommonMark specification for both.

I’m not sure about saying "fenced code blocks the more popular choice in the Rust community” because it seems like I’m speaking for everyone, but I can’t think of a better way to phrase it!
aidancully/rust,GBGamer/rust,aidancully/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,graydon/rust,graydon/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,graydon/rust,GBGamer/rust,aidancully/rust,aidancully/rust,graydon/rust,GBGamer/rust,graydon/rust,aidancully/rust