Fix issues noted by igor/manlint

- Fix typos [1]:
-- manged -> managed
-- specifiying -> specifying
- 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
@@ -145,10 +145,10 @@ ATF provides a C++ programming interface to implement test programs.
 C++-based test programs follow this template:
 .Bd -literal -offset indent
 extern "C" {
-.Ns ... C-specific includes go here ...
+\&... C-specific includes go here ...
 }
 
-.Ns ... C++-specific includes go here ...
+\&... C++-specific includes go here ...
 
 #include <atf-c++.hpp>
 
@@ -182,7 +182,7 @@ ATF_TEST_CASE_BODY(tc3)
     ... third test case's body ...
 }
 
-.Ns ... additional test cases ...
+\&... additional test cases ...
 
 ATF_INIT_TEST_CASES(tcs)
 {
@@ -202,7 +202,7 @@ To define test cases, one can use the
 .Fn ATF_TEST_CASE_WITH_CLEANUP
 or the
 .Fn ATF_TEST_CASE_WITHOUT_HEAD
-macros, which take a single parameter specifiying the test case's
+macros, which take a single parameter specifying the test case's
 name.
 .Fn ATF_TEST_CASE ,
 requires to define a head and a body for the test case,
@@ -232,7 +232,7 @@ opening and closing brackets.
 Additionally, the
 .Fn ATF_TEST_CASE_NAME
 macro can be used to obtain the name of the class corresponding to a
-particular test case, as the name is internally manged by the library to
+particular test case, as the name is internally managed by the library to
 prevent clashes with other user identifiers.
 Similarly, the
 .Fn ATF_TEST_CASE_USE