docs: Fix typos and grammatical errors

[vinayak42]

Fixes

Checklist

• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the [Contribution Guide] and my PR follows them.
• I updated my branch with the master branch.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation about the functionality in the appropriate .md file
• I have added in line documentation to the code I modified

Short description of what this PR does:

• Fixes typos and grammatical errors

If you have questions, please send an email to Sendgrid, or file a Github Issue in this repository.

[SendGridDX]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #88 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #88   +/-   ##
=======================================
  Coverage   99.32%   99.32%           
=======================================
  Files           2        2           
  Lines         149      149           
=======================================
  Hits          148      148           
  Misses          1        1

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[vinayak42]

@hugovk Applied changes as suggested

[thinkingserious]

Hello @vinayak42,

Thanks again for the PR!

We appreciate your contribution and look forward to continued collaboration. Thanks!

Team SendGrid DX