fix tox.ini lint section and mypy issue

[Elnaril]

What was wrong?

tox was not running the lint section, as describe here
Once fixed, a lint error was raised.

How was it fixed?

The header of the lint section in tox.ini was fixed.

The # type: ignore that was causing the mypy error was not needed anymore, since the underlying issue was fixed.

To-Do

• Add entry to the release notes

Cute Animal Picture

[Elnaril]

CI is not launched automatically ?
Anyway, this PR is ready for review :)

[Elnaril]

BTW, do I need to add a release note ?

[kclowes]

CI is not launched automatically ?

There is some permissions thing where it isn't launched automatically for (first time?) third party contributors.

BTW, do I need to add a release note ?

I'll add a release note to trigger the build. Thank you!

[fselmo]

Thanks for picking up on this @Elnaril ... I factored out some of this to keep a lint tox command to not break our Makefile.

@kclowes this looks good to me... can you take a last peek?

[Elnaril]

Thanks for picking up on this @Elnaril

My pleasure! :)

[kclowes]

Looks good to me! Thanks @Elnaril and @fselmo!