added pickles, Gentoo Docs and 13-point listicle

[eternaltyro]

Although Arch Linux Wiki is awesome, I can't say it's beautiful. So adding the following

Gentoo Handbook and Documentation: Documentation for the popularly most difficult (relatively) mainstream Linux operating system. These documents do an awesome job of instructing users in any level on how to install, configure and maintain Gentoo.

13 things people hate about your opensource docs: Nice article on things to focus on when dealing with open source documentation

Pickles: From their site """Pickles is an open source living documentation generator that works on feature files written in the Gherkin language, popularized in tools like Cucumber and SpecFlow. Pickles can be incorporated into your build process to produce living documenation in a format that is more accessible to your clients. Gherkin language files are written in plain text and stored in your source folder. This can make them inaccessible to clients who may not know how to work with source control or who are not interested in seeing all of the source code, just the features.
"""

[PharkMillups]

Hey there. Thanks for the PR and sorry it took me over 365 days to respond. I'm going to cherry pick a few things from this and merge them manually.

• I can't bring myself to incorporate a listicle. Are those real things?
• Pickle looks slick. Happy to merge that.
• Two Gentoos is one too many. :) Pick you favorite and open another PR.

Thanks.

[PharkMillups]

Closed by c8e52b5.