forth test cleanup

[bcpeinhardt]

Some of the tests weren't running because they weren't named properly (the function names have to end in _test).
I've also rewritten the test "defining_words_with_odd_characters_test" because it was the only test which
required two "statements" on the same line, but I don't think that's what it meant to test.

[lpil]

Thank you!

This is such an easy mistake to make, good evidence that we need to revisit how tests work in Gleam

[bcpeinhardt]

Idk, I kinda like the whole _test convention. In rust I'm constantly forgetting to write #[test] or #[tokio_test] and I can't ever remember the compiler or clippy asking me if I meant to make the method a test. I don't think it's a mistake I wouldn't make in another language haha.