Alt+Q reflow: behaviour change: text is moved on the same line as the opening brace

With Racket 6.6.0.5 (20160914-62f5b2c):

#lang scribble/manual
@defproc[(+ [x integer?] [y integer?]) integer?]{
 AAA BBB CCC DDD EEE FFF GGG HHH III JJJ KKK LLL.}

Pressing Alt+Q with the cursor somewhere in AAA … moves the AAA … on the same line as the opening brace:

#lang scribble/manual
@defproc[(+ [x integer?] [y integer?]) integer?]{ AAA BBB CCC DDD EEE FFF GGG
 HHH III JJJ KKK LLL.}

I think this was not the case before, and I personally preferred the old behaviour, because when the description for a @defproc is a large paragraph and the datum+contracts themselves span several lines, having the first line of description on the same line as some of the contracts doesn't make things very clear.

Reproduce the Alt+Q reflow behavior using the Scribble example in the issue, with the cursor in the description text. Start from the Alt+Q reflow command and compare the resulting line placement with the reported behavior; done means the opening brace and description follow the intended layout without moving text unexpectedly onto the brace line.