[docs] [issue21739] Add hint about expression in list comprehensions (https://docs.python.org/2/tutorial/datastructures.html#list-comprehensions)

Ezio Melotti added the comment: If we don't want to go into the details of why it's not equivalent, using "roughly equivalent" might be enough. ---------- keywords: +easy nosy: +ezio.melotti stage: -> needs patch type: -> enhancement _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue21739> _______________________________________