docs/autogen_shortcuts.py: support Python 3.8...
docs/autogen_shortcuts.py: support Python 3.8
In 64e72a955 (Restore shortcuts in documentation, define identifiers,
2023-01-08), some typing annotations were added to
docs/autogen_shortcuts.py using the builtin container type 'list'. This
feature is only available starting in Python 3.9 [1], but setup.cfg
lists Python 3.8 as the earliest supported Python version. This leads to
a failing documentation build in a Python 3.8 virtual environment.
Fix this by using the capitalized name 'List' from the 'typing' module
to keep Python 3.8 compatibility.
[1]
https://docs.python.org/3/whatsnew/3.9.html#type-hinting-generics-in-standard-collections
