pest3 early alpha prototype small update

[tomtau]

The new version of the early alpha prototype of pest3 was published on crates.io! The features are similar to the original early prototype version described in detail here: #1016 with two notable changes:

1. The crates were re-structured, so that it can be used as a single crate dependency in Cargo.toml as follows:

pest3 = { version = "0.0.1", features = ["derive"] }

In the code, Parser can be imported directly (instead of from pest3_derive):

use pest3::Parser;

2. The built-in rules were renamed to lowercase, e.g. pest::soi and pest::eoi instead of pest::SOI and pest::EOI.

What's (most likely) next

• Add support for "Meta-rules" pest3#8
• validation and refactoring:
  • Add debbugging tools - validation and interactive debugger pest3#17
  • Refactor: separate parsing and output generation via events pest3#11

[tomtau]

As always, anyone's help in pest3 development would be much appreciated, so feel free to head to https://github.com/pest-parser/pest3/ and happy hacking! (But again, be aware that the prototype codebase is not in the best shape at the moment, so it's primarily for more adventurous minds at this stage!)