docs(Grid): fix typo in GridExampleStretched example description

[sgarrity]

The description of the stretched property of a grid row mentioned 'width', but should have mentioned 'height'.

[welcome]

💖 Thanks for opening this pull request! 💖

Here is a list of things that will help get it across the finish line:

• Run yarn lint locally to catch formatting errors. This will fix some errors automatically, commit and push any changes.
• Run yarn test locally to catch errors. This ensures all components still behave as they should.
• Run yarn start to run the doc site locally and try a few pages, ensuring everything is in good working order.
• Include tests when adding/changing behavior.

We get a lot of pull requests on this repo, so please be patient and we will get back to you as soon as we can.

[codecov-io]

Codecov Report

Merging #3167 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3167   +/-   ##
=======================================
  Coverage   99.92%   99.92%           
=======================================
  Files         163      163           
  Lines        2746     2746           
=======================================
  Hits         2744     2744           
  Misses          2        2

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3e4243a...30d2353. Read the comment docs.

[welcome]

Congrats on merging your first pull request! 🎉🎉🎉

[levithomason]

Released in [email protected].