Use the same capitalisation as `rust-bitcoin` in identifiers that include 'pubkey'

[tcharding]

We have ScriptPubkey but it looks like rust-bitcoin is going to use ScriptPubKey - we should use the same here. May not need changing until we upgrade rust-bitcoin version, I did not look. Wanted to flag the issue anyways.

rust-bitcoin/rust-bitcoin#4950

[tcharding]

And in docs use the same format, scriptPubkey or scriptPubKey whatever we land after reaching consensus.

[jamillambert]

Core uses scriptPubKey in gettxout so we should probably too, although after doing all the RPCs for this crate I am not at all confident it is consistent in Core.

[tcharding]

after doing all the RPCs for this crate I am not at all confident it is consistent in Core.

Lol, that is my overall feeling also.