Document use isms / use isms <C++>

doc/Language/pragmas.pod6

@@ -86,11 +86,11 @@ fatal>:
 
 =item B<invocant> [NYI]
 
-=item X<B<isms>|isms> [2018.06 and later]
+=item X<B<isms>|isms> [2018.09 and later]
 
 Allow for some other language constructs that were deemed to be a trap that
 warranted a warning and/or an error in normal Perl 6 programming.  Currently,
-only C<Perl5> is allowed, which disables a bunch of P5isms warnings and errors.
+C<Perl5> and C<C++> are allowed.
 
 =begin code :skip-test<compilation error>
     sub abs() { say "foo" }
@@ -107,8 +107,12 @@ not make the compilation error go away.
     sub abs() { say "foo" }
     abs;   # foo
 
-By specifying C<use isms>, the compiler will allow the offending Perl 5
-construct, allowing the code to actually be executed.
+With this, the compiler will allow the offending Perl 5 construct, allowing
+the code to actually be executed.
+
+If you do not specify any language, all known language constructs are allowed.
+
+    use isms;   # allow for Perl5 and C++ isms
 
 =item X<B<lib>|lib> This pragma adds subdirectories to the library search
 path so that the interpreter can