docs: fix typos

[Lioness100]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

This PR fixes a few random typos (this was a trial run for a CLI I made)

Does this PR introduce a breaking change?

I don't think so, but I did notice that ConsumerReceivedUnsubcribedTopicsEvent (now ConsumerReceivedUnsubscribedTopicsEvent) was exported, so maybe.

[coveralls]

Pull Request Test Coverage Report for Build c886a2e3-2afc-4193-86a8-b19bff25dcc4

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 92.881%

---

Totals
Change from base Build e0f372e0-79c0-4b51-b146-6c89c18e535c:	0.0%
Covered Lines:	6484
Relevant Lines:	6981

---

💛 - Coveralls

[kamilmysliwiec]

LGTM