Provide a message builder option

[BioPhoton]

Thanks for the great lib front off! Really well documented and structured.

Motivation

As a developer I want to have full control of the created error message.
Examples of what I want to control is:

• all data displayed in the message (e.g. apply different pathoining)
• text of the displayed message
• font style of the message (for terminal usage)

Acceptance criteria

• implement a messageBuilder(issue: ZodIssue): string option so I can have full control of the error.

[jmike]

Yes, that is a good suggestion that would also address #311

I cannot commit on a delivery time, but I would like to work on it.

[jmike]

@BioPhoton would you be so kind as to review the PR that implements MessageBuilder here (#363)?

If you don't are unable to go through the code, then at least read the docs and let us know if this is what you also had in mind.

[jmike]

I expect the new MessageBuilder to land on npm on the week of Sep 16 (early). Stay tuned.