[phobos] [D-Programming-Language/phobos] 1a2ef5: document that chunkSize must be greater than zero

[GitHub via phobos]

  Branch: refs/heads/master
  Home:   https://github.com/D-Programming-Language/phobos
  Commit: 1a2ef5392390881fff832a8931f6ce004e4373d0
      https://github.com/D-Programming-Language/phobos/commit/1a2ef5392390881fff832a8931f6ce004e4373d0
  Author: anonymous <aG0aep6G at users.noreply.github.com>
  Date:   2015-12-07 (Mon, 07 Dec 2015)

  Changed paths:
    M std/range/package.d

  Log Message:
  -----------
  document that chunkSize must be greater than zero

There's an assert(chunkSize != 0) in the constructor which needs to be
documented.


  Commit: c723d17e9f27d770f10db220782405529d4451dc
      https://github.com/D-Programming-Language/phobos/commit/c723d17e9f27d770f10db220782405529d4451dc
  Author: Robert Schadek <robert.schadek at informatik.uni-oldenburg.de>
  Date:   2015-12-07 (Mon, 07 Dec 2015)

  Changed paths:
    M std/range/package.d

  Log Message:
  -----------
  Merge pull request #3858 from aG0aep6G/10087

document that chunkSize must be positive


Compare: https://github.com/D-Programming-Language/phobos/compare/61b07a39b129...c723d17e9f27