Add translate_from feature to translator_cog and its tests

[Eyad-Jawad]

• Add the feature on issue #127, which is to add translate from to translator_cog
• Add tests for translator_cog and the helper function language_autocomplete
• Add conftest.py to be used for all test files

[chrisdedman]

LGTM. Other than the test method that does not follow our convention (please, make changes), I am good with it. Please, @PenguinBoi12 have a second review.

[chrisdedman]

Can you follow our testing naming convention:
test_<action>__expect_<result> and test_<action>__with_<modifier>__expect_<result>

[PenguinBoi12]

In general it looks good to me but has @chrisdedman pointed out, we prefer when test follow this convention: test_<function/method/action>__expect_<result> and test_<function/method/action>__<modifier>__expect_<result>

For example:

• test_translator becomes test_translator__expect_embed_with_translation
• test_language_autocomplete_ara_input becomes test_language_autocomplete__with_partial_input__expect_matching_languages

You also need to test both the happy paths (test works as intended) and unhappy paths. For example, you should test what happens when the translators receive a bad input (like a language that doesn't exists). Many of your test do not test those correctly.

Otherwise, good job! It's a good first open-source contribution.

[PenguinBoi12]

If we default to "auto", I don't think it's relevant to allow None:

translate_from: str = "auto"

[PenguinBoi12]

I think, since we can now add translate_from , it could be cool to add english as a default to translate_into:

translate_from: str = "english"