I think the article is really general advice about (tech) writing, not about writing a programming book. There is very little if anything specific to programming itself, e.g. e.g. the types of code fragments you should use as examples.
Also, apart from the line:
> You can always ask feedback from people you trust to gain confidence
there is no mention of getting someone to proofread or even copy edit the book. This would also seem really important for a programming book - e.g. to check that the examples work away from the author's dev environment.
Also, apart from the line:
> You can always ask feedback from people you trust to gain confidence
there is no mention of getting someone to proofread or even copy edit the book. This would also seem really important for a programming book - e.g. to check that the examples work away from the author's dev environment.