docs: Add links to Syntax page for each feature

[richb-hanover]

The Syntax page provides a terrific summary of the features of PRQL. This PR adds links (and a few new examples) from each feature to the relevant page in the Book.

This also disables Prettier for the table, since it wants to reformat all the spacing to align the column marks.

[aljazerzen]

Looking good. I didn't know you can link directly to the titles.

[richb-hanover]

I didn't know you can link directly to the titles.

Yes - Good websites usually set an id="..." on or just above the heading. I find it by right-clicking on the heading in the browser, choosing Inspect from the dropdown and examining the HTML to find the id. Then tack that ID onto the end of the URL with #whatever-the-id-was

[max-sixty]

Thanks a lot @richb-hanover !

Did we exclude the annotations deliberately? It is quite niche so may well make sense...

[max-sixty]

This is much easier to navigate!

[aljazerzen]

Did we exclude the annotations deliberately?

See my suggestion under a "resolved" comment