Create a "Testing Applications" subsection in devel-examples

[saivann]

Live previews: (Merged)

This pull request mostly re-uses existing (great) regtest / testnet texts and moves them into a dedicated subsection for higher visibility and so anyone can easily refer & link to them.

Since they are more likely to be referred often from devel-examples and not from devel-guide, I've also moved the "Bitcoin Core setup instructions", and applied a consistent introduction for each page (this also lets us avoid repeating some of this information in "Transaction" examples).

I also needed to fix one regex and some code blocks syntax to prevent autocrossref.rb from inserting links in code blocks (it was replacing "regest" in some of them).

[harding]

I'm wondering if there's a way to have all three documents use the same h2 sections (or almost the same). What do you think about changing this to an h3 under an h2 titled "Bitcoin Core", and then changing the Bitcoin Core APIs h2 in devref to also be "Bitcoin Core"? (At some point we might even add a Bitcoin Core h2 to the devguide.)

[saivann]

It is true that these examples are specific to Bitcoin Core, but are you aware of other implementations offering similar testing tools? I actually like the idea of providing a "Testing applications" prominent link because we really want people to experiment there and link to it. So I'm afraid it would be "buried" if we were to move it under "Bitcoin Core".

[saivann]

@harding In case you like the idea, I also imagined this subsection could provide examples and links to more testing tools over time (e.g. Gavin's payment request generator - examples and link to source code).

[harding]

I think it isn't that important---one of the things I like about the way Kramdown creates its automatic head anchors is that they're tied to the text, not the header depth. That means we can always rearrange sections and subsections later. I say we try it your way and see how we feel about it in a few months.

[saivann]

@harding Agreed on re-accessing where this should be located later. I was (maybe wrongly) assuming regtest / testnet will be used often (not just from the Transaction examples). Anyway I think the important part is to have these instructions easily "findable" and "linkable". I'm not sure about having the same "Bitcoin Core" subsection in devel-[guide/ref/examples] though, as it seemed good to me to avoid duplicating content, and mixing examples / references / guide content altogether.

[harding]

I notice that you use <!--[-->`term`<!--]--> a lot.  
Did you know that you can also use your more elegant noref here?
E.g. `term`<!--noref-->

[saivann]

@harding Right! But I would need to define regtest in _autocrossref.yaml, so I appreciated your fallback method better. But any of these are fine to me :)

[harding]

Should probably mention that they need to do everything in the setup including maturing the first coinbase. For example: ...and create a regression test mode environment with 50 BTC in your test wallet.

[harding]

"Explanations" sounds worse to my ear than the original "information", possibly because information is neutral but explanation is often used in modern English to mean "justification of wrongdoing."

[harding]

API should be singular (adjectives in English are almost always singular).

[harding]

Re: noref: actually, we changed it to ignore everything except whitespace, so even this should work without any additional definitions:

`regtestmode1234(*&^%/`_-+=!<!--noref-->

[saivann]

@harding Thanks! I updated the pull req and live preview with your feedback.

Re: noref, that's strange, I had issues using it previously but for some reason, everything works fine now as you were suggesting, thanks!

In the absence of critical feedback, this pull request will be merged on June 14th.

[harding]

@saivann LGTM. Thanks!