feat(sol-macro): helper builders for errors and events

[0xrusowsky]

Motivation

Constructing error/event enum variants is verbose — you repeat the variant name as both the enum discriminant and the inner struct constructor.

Solution

Generate snake_case constructor helpers, on {Contract}Errors and {Contract}Events enums, which flatten that into a single call with the fields as arguments.

  // before
  let err = IExampleErrors::ErrorWithFields(ErrorWithFields { available: val, token: addr });
  let event = IExampleEvents::EventWithoutArgs(ErrorWithoutArgs {});

  // after
  let err = IExampleErrors::error_with_fields(val, addr);
  let event = IExampleEvents::event_without_args();

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes