experimental: (?{...}) and (??{...})

I think this one is simple.  These constructs were introduced in v5.6, and I
propose to document that the experiment ended (successfully) in 5.18.0.

Dissention welcome, and Dave M.'s vote counts extra. ;)

-- 
rjbs

• experimental: (?{...}) and (??{...}) by Ricardo Signes
• Re: experimental: (?{...}) and (??{...}) by Zsbán Ambrus
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by Ricardo Signes
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by Ruslan Zakirov
• Re: experimental: (?{...}) and (??{...}) by Ricardo Signes
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by Aristotle Pagaltzis
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by Dave Mitchell
• Re: experimental: (?{...}) and (??{...}) by Steffen Mueller
• Re: experimental: (?{...}) and (??{...}) by Leon Timmermans
• Re: experimental: (?{...}) and (??{...}) by Dave Mitchell
• Re: experimental: (?{...}) and (??{...}) by Zsbán Ambrus
• Re: experimental: (?{...}) and (??{...}) by Leon Timmermans
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by Ricardo Signes
• Re: experimental: (?{...}) and (??{...}) by Ricardo Signes
• Re: experimental: (?{...}) and (??{...}) by Aaron Crane
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by Aristotle Pagaltzis
• Re: experimental: (?{...}) and (??{...}) by Reverend Chip
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by Deven T. Corzine
• Re: experimental: (?{...}) and (??{...}) by Leon Timmermans
• Re: experimental: (?{...}) and (??{...}) by Leon Timmermans
• Re: experimental: (?{...}) and (??{...}) by demerphq
• Re: experimental: (?{...}) and (??{...}) by Rev. Chip
• Re: experimental: (?{...}) and (??{...}) by Eric Brine
• Re: experimental: (?{...}) and (??{...}) by Ricardo Signes