Fix camelCase name in Mojo stdlib

[gryznar]

Mojo in Testing library has names in camelCase, as Python in unittest. I do not catch arguments on that and I disagree with them.

1. It is incostinent with PEP8
2. This is not the case of compatibility, because Mojo could have assert_equal and this won't break compatibility with unittest.TestCase::assertEqual()
3. Core Python developers would choose snake_case in unittest if they could do it one more time
4. Only Testing module has camelCase
5. A lot of people from Python community do not care about unittest and use pytest instead
6. If Mojo would have 100% compatibility with Python it can just import unittest / pytest or any other lib and use it instead of stdlib Testing
7. If someone would like to find method for assertion equality he won't search for "assertEqual", but will look into docs / ask someone or search for term "assert" / "fn assert" or similar
8. Idea to make names in Mojo stdlib the same as in Python (if it is not the case of compatibility) can make a headache in maintanance very quickly

[lattner]

Yep, this is simply a mistake. @stumpOS do you know who owns this code? Can you take a look?

[lattner]

Mojo is a member of the Python family. You're right that some naming is subjective, but PEP8 is pretty widely adopted across the Python community - I don't see a reason for Mojo to diverge.

[gryznar]

It is fixed, topic could be closed