Antoine Stevan 07d7899a97
remove def-env and export def-env (#10999)
follow-up to
- https://github.com/nushell/nushell/pull/10715

> **Important**
> wait for between 0.87 and 0.88 to land this

# Description
it's time for removal again 😋 
this PR removes `def-env` and `export def-env` in favor of `def --env`

# User-Facing Changes
`def-env` and `export def-env` will not be found anymore.

# Tests + Formatting

# After Submitting
2023-11-19 23:25:09 +08:00
..
2023-02-27 13:58:56 -08:00