Fix typo in `HotellingT2Test` name

[nalimilan]

Introduced by #158.

[ararslan]

Thank you! Do you think it'd be worth adding a deprecation for the old name? Though it looks like no registered packages are referencing it^1 so it should be safe to just change.

[nalimilan]

Given how ridiculous the old name is, I'd say we can assume nobody uses it or it would have been reported. :-)

[ararslan]

You mean you've never used Hotelling's $T^2$ test test? It's twice as powerful as Hotelling's $T^2$ test, but not nearly as powerful as Hotelling's $T^2$ test test test.