drop string extension to not pollute methods

[brphelps]

Proposed changes

This is dropping the definition of truncate on String -- this seems to pollute the method in my usages, where the default rails method gets replaced with a method that doesn't match the signature.

https://github.com/0llirocks/cvss-suite/issues/39

Types of changes

What types of changes does your code introduce to CvssSuite? Put an x in the boxes that apply

• [X] Bugfix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR.

• [X] Unit tests pass locally with my changes
• [X] I have added tests that prove my fix is effective or that my feature works
• [ ] I have added necessary documentation (if appropriate)