emails: Fix two grammar nits.

[jrowan]

No description provided.

[smarx]

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[jrowan]

As a related question/nit, we use both the space-around style -- like this -- and the directly-abutting style--this one--for em dashes, even within those that are spelled out as — in an html setting (it varies by email/place in the documentation). For plain text emails, the spaces look good, so maybe we should default to spaces everywhere (this is what the Associated Press style guide recommends, but most other ones suggest no spaces around the em dash). Maybe it's worth documenting a set of rules for grammar/usage/spelling of copy and help text somewhere the way we do for code style.

[timabbott]

Sounds reasonable to me. We could start with a text style guide in docs/text-style.md and grow it over time. @synicalsyntax FYI, you may be interested in this concept as well.

[timabbott]

Merged, thanks @jrowan!