Clarify missing nonce use

[aryzing]

Description

The way possible_next_nonce is calculated wasn't explicitly defined, previously using the term "derived", making it harder to understand whether missing nonces should be inspected when creating new transaction or trying to get existing transactions unstuck.

The changes include more explicit language, as well as minor changes more aligned with how Nakamoto works (no more mention of microblcks).

Type of Change

• New feature
• Bug fix
• API reference/documentation update
• Other

Does this introduce a breaking change?

No, just docs were updated

Are documentation updates required?

It would be nice if the API docs were updated too, since the reason I came here (and asked on Discord) was because the API docs didn't seem to be clear enough

Checklist

• Code is commented where needed
• Unit test coverage for new or modified code paths
• npm run test passes
• Changelog is updated
• Tag 1 of @rafaelcr or @zone117x for review

[CLAassistant]

All committers have signed the CLA.

[ryanwaits]

@aryzing Thanks for the PR! These docs have been moved to our dedicated docs repository - I'll migrate your suggested changes there.

PR: hirosystems/docs#799