Add footnote for 'programming with collections'.
Add reference to 'monadic regions'.
Mention Prolog as the only known example of a homoiconic language other than Lisp.
Remove tooling specifics related to Lisp.
Rotate triangle symbol when Tool Details section hidden/shown.
Remove incorrect equating of the null and bottom types.
Mention Objective-C as unique for automatic reference counting.
Regenerate diagrams for language properties article.