chore(codegen): error to prevent undesired behavior

[jeertmans]

Hi @maciejhirsz !

This PR follows what was discussed in #302.

I added a small check in logos-codegen to check for .* or .+ patterns. When found, an error is raised with a helpful message that redirects to a solution.

I hope the implementation is correct (especially for non-utf8 cases and the fact that I also added a check for .+).

NOTES

1. I had to move the doc tests from tests/tests/binary.rs to tests/src/lib.rs because I don't think they were ever executed;
2. I think that the pattern you mentioned in Incorrect regex #302 (comment), namely r"\([^)]*\)", is missing an \ to escape the inner );
3. and I added new tests that assert a compile error is raised for the given cases.

[maciejhirsz]

Thanks for doing this!

[maciejhirsz]

Cheers!