chore: spelling and grammar. fix #11480

[warmsocks]

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other, please describe: Spelling and grammar

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• It's submitted to the dev branch for v2.x (or to a previous version branch), not the master branch
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• All tests are passing: https://github.com/vuejs/vue/blob/dev/.github/CONTRIBUTING.md#development-setup
• New/updated tests are included

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

Other information:
This is a drive-by contribution, and I had trouble testing on my host. When I ran npm test, everything succeeded/passed until attempting to start a webserver, since I already have something listening on port 8080 that I didn't want to shut down. I tried _npm test --port 8111, which looked like it was going to work, but there are a bunch of hard-coded instances of :8080 under e2e/specs that I think are the cause. I'll open a separate issue for that.

[posva]

Thanks!
Since this change is only related to comments, you don't even need to run the test suit 😄