docs: fix a few typos in CONTRIBUTING.md

[dannon]

Summary of the Pull Request

Fixes typos in CONTRIBUTING.md

PR Checklist

• [x] Dev docs: Added/updated if needed

Detailed Description of the Pull Request / Additional comments

Very minor, just noticed a few typos in CONTRIBUTING.md when I was trying to look up how to capture logs and report bugs. The first two are the main bit, then standardized usage of Windbg/WinDbg/windbg in text (command usage unchanged)

Validation Steps Performed

N/A