Use ".Sy root" instead of ".Em root" when talking about the root user.

Replace MANDOCPROG with "mandoc" now that MANDOCPROG has been removed.

docs/sudo_plugin_python.man.in

@@ -1884,14 +1884,14 @@ will not load the Python interpreter or the Python libraries.
 .PP
 By default, a Python plugin can only import Python modules which are
 owned by
-\fIroot\fR
+\fBroot\fR
 and are only writable by the owner.
 The reason for this is to prevent a file getting imported accidentally
 which is modifiable by a non-root user.
 As
 \fBsudo\fR
 plugins run as
-\fIroot\fR,
+\fBroot\fR,
 accidentally importing such file would make it possible for any user
 (having write access) to execute any code with administrative rights.
 .PP