Update README.md

[freddy1020]

1. It looks like an unnecessary comma
2. "a multitude of" seems wordy, just use "many"
3. Remove "on" and "is" -> "are"
4. It may unclear what "this" reference to, just rewrite this sentence to make it easier to understand.
5. "it" -> "them"
6. Rewrite this sentence to make it more clear to follow
7. "information about exams" -> "exam information"
8. remove some unnecessary comma

[hashicorp-cla]

All committers have signed the CLA.

[VioletHynes]

As this PR is older and cannot currently be merged due to merge conflicts, I’m going to go ahead and close it. Please feel free to open a new PR if your desired changes are still applicable!