JQ DOCs: add section links to keywords

[nyurik]

I would like to propose the JQ manual to have all keywords into links to the corresponding topic. For example, every time reduce is written as a keyword (red text), it should link to #Reduce docs section. This will make searching / navigating the docs far easier. Thank you!

P.S. for bonus points, navigating to a section via an anchor should also expand corresponding examples, but this might be a separate (and far more complex) task.

[nicowilliams]

Sure. We might like to replace the manual with something more like this enhanced with a description of the jq processor.