According to info groff (section 5.11 Character Translations),
\. should print just the dot. However, this is not what seems to happen.
If I render this manpage
.TH x x x x
\.SH foo
I get foo rendered as a section heading, and .SH is not printed.
So, why does this happen, and how do I escape the dot (and the apostrophe) at the begginning of the line in groff?