Various corrections to developer reference

[achow101]

Corrected Compact Size Unsigned Integer description to include the lower bounds.

Changed reject message code descriptions of the extra data field to be more accurate as the extra data is not always what was specified nor is the field required.

Clarified the empty message headers are allowed.

Removed incorrect note in importaddress which stated that addresses would not be rescanned if already in the wallet. They are rescanned.

Closes #1505, #1365, #1604, #1520

If this is accepted, please pay the bounty to 1AjFwHanPewurVms4Z3ExtapHmKWF6aTVS

[harding]

@achow101 in and of themselves, these changes LGTM. I was wondering if you checked the implementation behavior to confirm all of those issues were accurate? (I'm not saying you have to, I don't know what @wbnns's bounty rules are, but I usually like to confirm the problems before editing the docs.)

In particularly, I'm surprised by #1520 (rescan) as I don't think I would've added the extra sentence there unless I believed it was true based on my reading of the code or my testing (though it's possible the implementation has changed since I wrote it, or that I was wrong when I wrote it, or that I'm wrong now in guessing at my mental state 2.5 years ago when I wrote it).

Also #1365 (compactSize canonical encoding) has a link to a Bitcoin Core dev saying that the sizes weren't previously enforced, suggesting to me that there may be some subtleties in the behavior or maybe that this was even an unknown soft fork.

[wbnns]

@achow101 Thanks for tackling this stuff! @harding Thanks also for the feedback.

Unless others object, this will be merged on Thursday, May 26th.

[achow101]

@harding

I did verify the behavior and checked in the code.

For the rescan functionality, it looks like the behavior did change with this commit bitcoin/bitcoin@983d2d9 so it no longer did nothing if the address/script already existed.

For the CompactSize uint encoding, that behavior changed with this commit: bitcoin/bitcoin@8dc206a to enforce canonical encoding.

[harding]

@achow101 awesome! Thanks!

[wbnns]

@achow101 Merged; Bounty paid together with #1610. 👍

[BangLy]

importaddress