Remove hyphen from case-sensitive/insensitive

[jamesscottbrown]

This makes the usage in the Key Points consistent with the body of the lesson, and the Glossary.

[henrykironde]

Thanks @jamesscottbrown, I had to look for this and I see what you mean.
Based on a reference from https://en.wikipedia.org/wiki/Case_sensitivity, how about we change the reference to use - ?

[henrykironde]

Thank you, @jamesscottbrown, for the contributions. We are closing since we have not gotten suggestions from the community. Feel free to reopen the issue.