v0.12.127: @newsroom.writer: a pull request by another name

A pull request by another name: Dinis asked for a review of release candidate 2 of Generation ZX Developers, chapter by chapter, in his voice, with the principles behind the changes, suggestions on pacing and structure, and what the newsroom does that the book could use. Six editors, one per part, made the cuts under one rule, never invent anything; a pass across the parts found the steps two editors had each cut and pointed to the other. Delivered as seven patches in an sgit vault: 74,666 to 64,351 words. Four figures (rp-patches, rp-overlap, rp-hole, rp-cover, the book drawn as a graph for the back cover), the photo of the printed copy reused, a graph, and the gen-z-book series tag.