Fixed dependencies of Pug and Pure

[RunDevelopment]

There were a few problems with the dependencies of Pug and Pure.

1. Pug did not require markup.
2. Pug had ejs, hogan, mustache, plates, and swig as peer dependencies, none of which are languages (or aliases) Prism supports.
3. Pure had ats and dsp as peer dependencies, none of which are languages (or aliases) Prism supports.

I removed the unsupported languages for now.

[RunDevelopment]

Might have to adjust Pug after #1769.