Change `language` arg to enum in `Mnemonic`

[DavidRomanovizc]

What was wrong?

Change the language param in mnemonics to an enum

Related to Issue #287 Closes #287

How was it fixed?

• Add an enum and change the language param
• Add deprecation warning for passing language param as str
• Also added docstring for the Mnemonic class and updated docs to show HD Account as a top-level module.

Todo:

• [x] Clean up commit history
• [x] Add or update documentation related to these changes
• [x] Add entry to the release notes

Cute Animal Picture

[pacrob]

Hey @DavidRomanovizc , we discussed this today and decided we'd like this not to be breaking. Sorry for lack of clarity in the initial issue. Keeping everything you've done, just allow Union[Language, str] in where language is an arg, and keep return types too. If you get to it, awesome, otherwise I'll put it together later this week. Thank you!

[DavidRomanovizc]

@pacrob, maybe adding wanrings.warn if isinstance(language, str) so that users pass it using an enum? And if it will necessary we change type annotations to language: Language in the future update

[pacrob]

Good idea, @DavidRomanovizc, deprecation warnings added. There's some major pypi funkiness going on, so I'll come back and verify CI passing tomorrow.

edit: NM, lookin' good! Needs some review from the team, but otherwise gtg.