support "nocite"?

[iveney]

First off, thanks so much for making this plugin! 😃

I am migrating my blog to use jekyll, where I used pandoc previously. It supports \nocite{xxx}, and is helpful when I don't need to explicitly cite the items, but simply print out a list of selected references. Therefore,

## References
{% nocite A B C %}

{% bibliography --cited %}

should ideally NOT generate [1][2][3] in place, but DO print out them upon bibliography is called:

References
1. ...
2. ...
3. ...

Probably not a super popular usage, but definitely helpful for my case. Appreciate if this can be supported!

[inukshuk]

Good idea! This should be really easy to implement if anyone would like to take a stab at it. Basically, just duplicate the cite tag and, instead of rendering the citation, just adding the keys to context['cited'] (currently, this happens here and here when rendering a citation).

For testing, one of these cited-only tests can be easily adapted.

[iveney]

Took a quick stab at it, when trying to add test I am running into the following. I can repro this even at master. Thoughts?

➜  jekyll-scholar git:(nocite) rake
/Users/ivanx/.rbenv/versions/2.7.1/bin/ruby -S bundle exec cucumber
Traceback (most recent call last):
	13: from /Users/ivanx/.rbenv/versions/2.7.1/bin/ruby_executable_hooks:22:in `<main>'
	12: from /Users/ivanx/.rbenv/versions/2.7.1/bin/ruby_executable_hooks:22:in `eval'
	11: from /Users/ivanx/.rbenv/versions/2.7.1/bin/cucumber:23:in `<main>'
	10: from /Users/ivanx/.rbenv/versions/2.7.1/bin/cucumber:23:in `load'
	 9: from /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/bin/cucumber:11:in `<top (required)>'
	 8: from /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/bin/cucumber:11:in `require'
	 7: from /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/lib/cucumber/cli/main.rb:8:in `<top (required)>'
	 6: from /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/lib/cucumber/cli/main.rb:8:in `require'
	 5: from /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/lib/cucumber.rb:6:in `<top (required)>'
	 4: from /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/lib/cucumber.rb:6:in `require'
	 3: from /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/lib/cucumber/parser.rb:2:in `<top (required)>'
	 2: from /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/lib/cucumber/parser.rb:2:in `require'
	 1: from /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/lib/cucumber/ast.rb:9:in `<top (required)>'
/Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/lib/cucumber/ast.rb:9:in `require': /Users/ivanx/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/cucumber-1.3.11/lib/cucumber/ast/step.rb:80: circular argument reference - name (SyntaxError)