chore: BIP32HDNode - SwiftLint clean up

[JeneaVranceanu]

Summary of Changes

Review only after #756 is merged

BIP32HDNode.swift - manual SwiftLint fixes.

Test Data or Screenshots

By submitting this pull request, you are confirming the following:

• I have reviewed the Contribution Guidelines.
• I have performed a self-review of my own code.
• I have updated my repository to match the develop branch.
• I have included test data or screenshots that prove my fix is effective or that my feature works.
• I have checked that all tests work and swiftlint is not throwing any errors/warnings.

[yaroslavyaroslav]

There's a conflict appeared @JeneaVranceanu

[cclauss]

Can this pull request enable swiftlint in pre-commit or is there more work required before swiftlint can be enabled?

[JeneaVranceanu]

Can this pull request enable swiftlint in pre-commit or is there more work required before swiftlint can be enabled?

There is more work required before we can enable swiftlint in pre-commit. We are not even halfway there.
I'll do my best to post updates regularly. Maybe will be able to eliminate all issues this week but it will likely be a combination of real fixes + // swiftlint:disable ... in places where we need heavy refactoring.

[JeneaVranceanu]

@yaroslavyaroslav @janndriessen Fixed conflicts.