Docs in the tree always win.
Let's start deleting them now, and replacing them with links to the in-tree docs, rather than updating them. They've been skewing out of date for a long time. When I was looking for information about how to do a revert, I found wiki docs about linking to revisions in Subversion which didn't mention Github, which gives a flavor for how outdated some of this stuff is.
Thomas, would you mind doing the honors for this document? Links for process docs should probably be to https://docs.twistedmatrix.com/en/latest/
since, for process information (unlike API information), trunk should be authoritative, not the latest release.