Fix some minor typos and style issues

[QuLogic]

Just a few things found with codespell.

[QuLogic]

Also fixed a few flake8 things and some invalid escape sequences.

[ajdawson]

Should the changes to versioneer.py and _version.py be made in versioneer itself and a new version deployed for cartopy? The changes you made are small so I don't mind changing the generated files in this case, but it might not be a sustainable path.

[QuLogic]

I tried re-generating from the latest versioneer, but the version we have is already a patched one from @pelson, so it makes for a much larger change, and doesn't support the version scheme we currently have set.

[ajdawson]

I tried re-generating from the latest versioneer, but the version we have is already a patched one from @pelson, so it makes for a much larger change, and doesn't support the version scheme we currently have set.

Something for another time then.