Fix igor/manlint issues with atf-c(3)

• Remove surrounding ellipses in i.e. section and add a comma before and after the i.e. reference [1].
• Fix typo (specifiying -> specifying) [1].
• Escape '.' at start of lines using & to tell the roff processor that the line isn't meant to be treated as a command [2].

Bump .Dd for the change

MFC after: 1 week
Reported by: igor [1], manlint [2]
Sponsored by: Dell EMC Isilon