Nu Development Update: Parser Refactor and Documentation

1st chunk of `blog/2019-10-11-twin0007.md`

14c2ec1c8be7895a5ff47d7cb85d2b732c6464028f7d6090000000010000038d

# This week in Nu #7

The first of the big refactors landed this week, with lots of work still in-progress.

- wycats landed a major rewrite of the parser to better handle external/internal as well as more accurate coloring ([#728](https://github.com/nushell/nushell/pull/728))
- twe4ked and chhetripradeep added docs ([#802](https://github.com/nushell/nushell/pull/802), [#797](https://github.com/nushell/nushell/pull/797), [#795](https://github.com/nushell/nushell/pull/795), [#794](https://github.com/nushell/nushell/pull/794), [#793](https://github.com/nushell/nushell/pull/793), [#792](https://github.com/nushell/nushell/pull/792), [#791](https://github.com/nushell/nushell/pull/791))
- daveremy for helping out with the contributor book ([#4](https://github.com/nushell/contributor-book/pull/4))
- Thanks to pizzafox, empath75, t-hart, ArekMiszcz, jordelver, daveremy, and jankeromnes for filing issues

Title: Nu Development Update: Parser Refactor and Documentation

Summary

This week's Nu update highlights a major parser rewrite by wycats to improve handling of external/internal commands and coloring accuracy. Additionally, several contributors added documentation and helped with the contributor book. The update also acknowledges contributors who filed issues.