Docs: Document the variety of markdown required [UXR]

[josmperez]

Incorporate feedback such as:

• Explain the version of Markdown (and what features are supported) in the READMEs on the plugins site.

[josmperez]

@jackw Is this a question you can field? (What variety of markdown do our plugins support?)

[jackw]

Explain the version of Markdown (and what features are supported) in the READMEs on the plugins site.

Which READMEs are you referring to here @josmperez ?

[josmperez]

The READMEs for the plugin examples. I believe the plugin developer wants to include markdown in their plugin and wasn't sure which flavor of markdown was supported.