Documentation under "Developer's Guide" wrong for "Development installation"

[sjoro]

Describe the bug
Documentation under "Developer's Guide" is wrong for "Development installation" and "Documentation"asking the use to run
pip install -e ".[all]"

When following the instructions and installing a new conda-environment quick eye in the terminal outputs can reveal the following warning

WARNING: satpy 0.49.1.dev83+g0f8bf8714.d20240614 does not provide the extra 'all'

Expected behavior
Update the instructions and/or define a new key in pyproject.toml, e.g. dev, which installs the desired/required dependencies.

Additional context
This change/bug may have been introduced when switching from setup.py to pyproject.toml?