Rename custom exceptions form *Exception to *Error

[Secrus]

Resolves: #162

[dimbleby]

nb this is a breaking change.

If you're going to make breaking changes, it's worth considering more cleanup than this.

• Some but not all of these begin Cleo, consistency would be desirable
• especially RuntimeError, which collides with the builtin RuntimeError, that's asking for mistakes.
• What do RuntimeError and CleoValueError mean that is different from the builtin RuntimeError and ValueError?
• What's the difference between a RuntimeError and a LogicError?
• What's a CleoSimpleError? in what sense are some of these simple and others not?
• and so on

I realise that you were likely just looking to do a small tidy-up and not get into all this. But breaking changes should be rare: and if you're going to make breaking changes anyway, then that's the opportunity to make such improvements.

[Secrus]

nb this is a breaking change.

If you're going to make breaking changes, it's worth considering more cleanup than this.

• Some but not all of these begin Cleo, consistency would be desirable
• especially RuntimeError, which collides with the builtin RuntimeError, that's asking for mistakes.
• What do RuntimeError and CleoValueError mean that is different from the builtin RuntimeError and ValueError?
• What's the difference between a RuntimeError and a LogicError?
• What's a CleoSimpleError? in what sense are some of these simple and others not?
• and so on

I realise that you were likely just looking to do a small tidy-up and not get into all this. But breaking changes should be rare: and if you're going to make breaking changes anyway, then that's the opportunity to make such improvements.

Thanks for your input, I appreciate it. I will look into what you pointed out. I am aware that those are breaking changes, but as far as I know, the next release is gonna be 1.0.0 which could be a good point to introduce such changes, especially since we are working towards better code quality with more flake8 checks and the introduction of type checking via mypy.

[neersighted]

LGTM; but I would like to see the doc strings introduced have consistent punctuation.

I'd also squash the two commits -- the entire codebase is broken after the first one, so I do not see any value in splitting them.