docs: Tiny usage fix ("e-mail" -> "email")

I needed to make an edit in this branch to verify part of our docs
process, so I found a Javadoc typo to fix. No code error, just took
out the hyphen in "e-mail" in a Javadoc comment.

Test: make ds-docs
Bug: 67515954
Change-Id: Icb9b2a9df0d7dfd697050735886adec80bc92ff8