We've had some preliminary support for Buildbot in Review Bot for the

past couple major releases, but it was never more than a prototype. It

leveraged buildbot try in order to run a build, but we had several

issues using this for anything real:

It made assumption about patch levels for diffs (which must be passed

   to buildbottry`), and those assumptions made this useless for

   non-Git-style diffs.
It didn't calculate or request any options that would be required in

   order to run changes from other SCMs, like Subversion or Perforce.
It may not have even really worked with Git, outside of limited

   setups (due to issues locating the repository).
There's no useful output that comes from buildbot try, aside from

   some debug information and a general "pass" or "fail" response, all

   of which ends up in the review body. We had no way to even get a link

   to the build.

The plan is to add formal Buildbot support as an integration in the

future, alongside CircleCI, Jenkins, and Travis-CI. For now, though,

we're scrapping this so that people don't end up getting frustrated

trying to configure a tool that won't work for them.
The old documentation page will remain, but won't be included in any

Table of Contents. This will help explain where the support went, and

direct people to an alternative solution.

Unit tests pass.
Built the docs. Verified the page wasn't in the table of contents, but

was available, and wasn't generating any warnings. Tested the links within.