Fix manlint issues with atf-check(1)

- Use `.Bf Em`/`.Ef` instead of prefixing lines with `.Em`. The forms
  are equivalent with traditional roff, but unnecessarily verbose. The
  former form applies the .Em macro to the enclosed block.
- Move EXIT_STATUS section down so the section complies with section
  ordering specified by mdoc(7) and enforced by manlint(1).

Bump .Dd for the change

MFC after:	1 week
Sponsored by:	Dell EMC Isilon

contrib/atf/atf-sh/atf-check.1

@@ -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 5, 2014
+.Dd March 6, 2017
 .Dt ATF-CHECK 1
 .Os
 .Sh NAME
@@ -40,10 +40,12 @@
 executes a given command and analyzes its results, including
 exit code, stdout and stderr.
 .Pp
-.Em Test cases must use
-.Em Xr atf-sh 3 Ns ' Ns s
-.Em Nm atf_check
-.Em builtin function instead of calling this utility directly.
+.Bf Em
+Test cases must use
+.Xr atf-sh 3 Ns ' Ns s
+.Nm atf_check
+builtin function instead of calling this utility directly.
+.Ef
 .Pp
 In the first synopsis form,
 .Nm
@@ -119,9 +121,6 @@ as a shell command line, executing it with the system shell defined by
 You should avoid using this flag if at all possible to prevent shell quoting
 issues.
 .El
-.Sh EXIT STATUS
-.Nm
-exits 0 on success, and other (unspecified) value on failure.
 .Sh ENVIRONMENT
 .Bl -tag -width ATFXSHELLXX -compact
 .It Va ATF_SHELL
@@ -129,6 +128,9 @@ Path to the system shell to be used when the
 .Fl x
 is given to run commands.
 .El
+.Sh EXIT STATUS
+.Nm
+exits 0 on success, and other (unspecified) value on failure.
 .Sh EXAMPLES
 The following are sample invocations from within a test case.
 Note that we use the