trivial: add missing rpc help messages, remove segwit references, dashify help text, undashify code comments

[kwvg]

Issue being fixed or feature implemented

This pull request is a follow-up to some feedback received on dash#5834 as the patterns highlighted were present in different parts of the codebase and hence not corrected within the PR itself but addressed separately.

This is that separate PR 🙂 (with some additional cleanup of my own)

What was done?

• This pull request will remain a draft until dash#5834 as it will introduce more changes that will need to be corrected in this PR.
• Code introduced that is unique to Dash Core (CoinJoin, InstantSend, etc.) has been excluded from un-Dashification as the purpose of it is to reduce backport conflicts, which don't apply in those cases.
  • CWallet::CreateTransaction and the CreateTransactionTest fixture have been excluded as the former originates from dash#3668 and the latter from dash#3667 and are distinct enough to be unique to Dash Core.
• There are certain Dashifications and SegWit-removals that prove frustrating as it would break compatibility with programs that rely on the naming of certain keys
  • getrawmempool, getmempoolancestors, getmempooldescendants and getmempoolentry return vsize which is currently an alias of size. I have been advised to retain vsize in lieu of potential future developments. (this was originally remedied in 219a1d0 but has since been dropped)
  • getaddressmempool, getaddressutxos and getaddressdeltas all return a value with the key satoshis. This is frustrating to rename to duffs for compatibility reasons.
  • decodepsbt returns (if applicable) non_witness_utxo which is frustrating to rename simply to utxo for the same reason.
  • analyzepsbt returns (if applicable) estimated_vsize which frustrating to rename to estimated_size for the same reason.

How Has This Been Tested?

Breaking Changes

None

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation
• I have assigned this pull request to a milestone (for repository code-owners and collaborators only)

[github-actions]

This pull request has conflicts, please rebase.

[knst]

utACK

Seems as there's no breaking changes in this PR.

Btw, PR description mentions some possible changes such as rename "non_witness_utxo" which annoys me too - let's prepare one more PR for v21?

[UdjinM6]

utACK

[PastaPastaPasta]

utACK for squash merge. No breaking changes detected. @thephez please confirm style is correct

[thephez]

Looks okay to me. Just one nit, but nothing that prevents merging.

[thephez]

Nit: imo the original wording was easier to understand

[kwvg]

The phrase "The state of the corresponding block ChainLock" was used more and seemed more concise.