fix(eslint-plugin): [no-unsafe-assignment] fix typo in message

[Chriscbr]

No description provided.

[typescript-eslint]

Thanks for the PR, @Chriscbr!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

---

🙏 Please, if you or your company is finding typescript-eslint valuable, help us sustain the project by sponsoring it transparently on https://opencollective.com/typescript-eslint. As a thank you, your profile/company logo will be added to our main README which receives thousands of unique visitors per day.

[codecov]

Codecov Report

Merging #2347 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2347   +/-   ##
=======================================
  Coverage   93.09%   93.09%           
=======================================
  Files         284      284           
  Lines        9097     9097           
  Branches     2499     2499           
=======================================
  Hits         8469     8469           
  Misses        302      302           
  Partials      326      326           

Flag	Coverage Δ
#unittest	93.09% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...es/eslint-plugin/src/rules/no-unsafe-assignment.ts	80.17% <ø> (ø)

[bradzacher]

Thanks!