Fixed some grammatical errors

[moi238]

• I have read freeCodeCamp's contribution guidelines.
• My pull request has a descriptive title (not a vague title like Update index.md)
• My pull request targets the master branch of freeCodeCamp.
• None of my changes are plagiarized from another source without proper attribution.
• My article does not contain shortened URLs or affiliate links.

If your pull request closes a GitHub issue, replace the XXXXX below with the issue number.

Closes #XXXXX

[ezioda004]

Thank you @moi238 for your contribution and congratulations on your first PR merge to this repo! 🎉