Update UpgradeGuide.rst Fixed spelling errors

[Aditya-Tripuraneni]

Problem: There were a few spelling mistakes and some punctuation could be improved. When some bullet points were listed the beginning of sentences were not capitalized.

-Fixed grammar -Added periods -Fixed punctuation

One of the spelling mistakes was knowning changed it to knowing. Changed On some conditions to In some conditions.

These changes will just fix the spelling errors that were present before and ensure that documentation is free of spelling errors and punctuation is on point.

[evilaliv3]

Dear @Aditya-Tripuraneni , i'm sorry for the delay reviewing this pull request.

I just looked into it and its all right! going to merge it right away, thank you for your contribution.