Update README around multi-dictionary changes

[peternewman]

No description provided.

[sebweb3r]

Would you mind to add a table with the existing dictionaries and shortly say, which are used as a default?

I know it now, but the information would be helpful for new people using the code.

[peternewman]

Would you mind to add a table with the existing dictionaries and shortly say, which are used as a default?

I don't really want to add something separately as it's just another thing to forget to update and become stale. It's within the help here:
https://github.com/codespell-project/codespell/blob/master/codespell_lib/_codespell.py#L269-L275

We could mention that somewhere on this page, but I'm not quite sure where.

[sebweb3r]

Adding a reference to the builtin section is fine for me. But if you just read the dictionary part and Readme, it is not really clear.

[larsoner]

I don't really want to add something separately as it's just another thing to forget to update and become stale.

I would add a tiny test (pytest) that looks for ../README.rst, does a quick parse, and checks that there is a match. That would mitigate the risk.

It would be good to have the dictionary list in human-readable form. We can also tell people to do codespell --help, where they all should be listed.

[larsoner]

@peternewman do you want to take a stab at a better phrasing inspired by #1535 so we can close that one when we merge this, then cut a release?

[larsoner]

Ping @peternewman , would be nice to move on this so we can release

[larsoner]

Thanks @peternewman

[peternewman]

Ping @peternewman , would be nice to move on this so we can release

Sorry @larsoner , various stuff got a bit mad, plus trying to hit a release deadline for something else I help maintain.

I'll generate some issues for the other things we discussed.