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

contrib/atf/atf-c/atf-c.3

@@ -22,7 +22,7 @@
 .\" IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 .\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 .\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-.Dd October 13, 2014
+.Dd March 6, 2017
 .Dt ATF-C 3
 .Os
 .Sh NAME
@@ -203,7 +203,7 @@
 ATF provides a C programming interface to implement test programs.
 C-based test programs follow this template:
 .Bd -literal -offset indent
-.Ns ... C-specific includes go here ...
+\&... C-specific includes go here ...
 
 #include <atf-c.h>
 
@@ -237,7 +237,7 @@ ATF_TC_BODY(tc3, tc)
     ... third test case's body ...
 }
 
-.Ns ... additional test cases ...
+\&... additional test cases ...
 
 ATF_TP_ADD_TCS(tp)
 {
@@ -259,7 +259,7 @@ To define test cases, one can use the
 .Fn ATF_TC_WITH_CLEANUP
 or the
 .Fn ATF_TC_WITHOUT_HEAD
-macros, which take a single parameter specifiying the test case's name.
+macros, which take a single parameter specifying the test case's name.
 .Fn ATF_TC ,
 requires to define a head and a body for the test case,
 .Fn ATF_TC_WITH_CLEANUP
@@ -299,7 +299,7 @@ library to do it for you.
 This is done by using the
 .Fn ATF_TP_ADD_TCS
 macro, which is passed the name of the object that will hold the test
-cases; i.e. the test program instance.
+cases, i.e., the test program instance.
 This name can be whatever you want as long as it is a valid variable
 identifier.
 .Pp