Release notes for 0.94.0 (#1378)

Release notes for `0.94.0`

* Edit 0.94.0 release notes (#1412)

* Write themes of this release

* Add toc links

* Add command changes

* Write excerpt

* Add `hide-env` change

* Add autogenerated content

* add some release notes targeted at plugin developers (#1417)

* Edit 0.94.0 release notes (#1415)

* Fix usages of `CWD` to `PWD`

* Fix typos and some rewording

* Add warning for removal of dataframes cargo feature

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Co-authored-by: Ian Manske <[email protected]>