* Fixed missing $ symbol and cleaned up code a bit.

Add missing spaces to help messages in config file

The specifier `~=0.9` is equivalent to `>= 0.9, == 0.*` so there is no need to specify `<2`.

Fix version of jupyter-packaging in pyproject.toml

* Fix issue #3218, add comment "// accessibility improvement" before each line changed

- Add the argument %f to the Exec key so that a notebook file can be directly opened from the file manager by right-click → Open With Jupyter Notebook, or by double-clicking (https://specifications.freedesktop.org/desktop-entry-spec/latest/ar01s07.html)
- Add the Keyword key so that the Jupyter Notebook application can be searched with a keyword "python", e.g. from GNOME Shell (look for the Keywords key in the table https://specifications.freedesktop.org/desktop-entry-spec/latest/ar01s06.html)
- Add a semicolon ";" to the end of the strings in the Categories key (look at the examples here https://specifications.freedesktop.org/menu-spec/latest/ar01s03.html)

* sanitizer fix

* Pass sanitizer options explicitly