Nushell Updates, RFCs, Documentation, and Scripts

1st chunk of `blog/2021-03-19-twin0082.md`

3d0299e85e872e0a48eb42596c7cd8f801a85042be7bcd8e0000000100000359

## Nushell

- fdncred added the ability to [create more complex unicode characters](https://github.com/nushell/nushell/pull/3195)
- nibon7 improved testing to [work in release mode as well](https://github.com/nushell/nushell/pull/3184)
- andrasio improved [testing infrastructure](https://github.com/nushell/nushell/pull/3179)
- ahkrr upgraded [rustyline to 8.0.0](https://github.com/nushell/nushell/pull/3167)
- John-Goff renamed [`count` to `length`](https://github.com/nushell/nushell/pull/3166)

## RFCs

- LhKipp added [an RFC about the config structure](https://github.com/nushell/rfcs/pull/5)

## Documentation

- kubouch added [a list of accepted parameter types](https://github.com/nushell/nushell.github.io/pull/111)

## Scripts

- fdncred updated [scripts to use the newly-renamed `length` command](https://github.com/nushell/nu_scripts/pull/31)

Title: Nushell Updates, RFCs, Documentation, and Scripts

Summary

This chunk summarizes recent updates to Nushell, including the addition of complex unicode characters, testing improvements, rustyline upgrade, renaming 'count' command to 'length', an RFC about the config structure, documentation updates for parameter types, and script updates to use the new 'length' command.