Fix some typos;

[eof273]

[google-cla[bot]]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

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[mjwilson-google]

As noted by the google-cla bot above, we need a signed CLA before we can merge the change.

Thank you for taking the time to find and fix all of these typos!

[hoch]

Since this PR became stale, I think we need to duplicate the contents and create a new PR.