Update pod.pod6

Use R<> as Pod

doc/Language/pod.pod6

@@ -612,19 +612,17 @@ B<replaceable item>, a placeholder, or a metasyntactic variable. It is
 used to indicate a component of a syntax or specification that should
 eventually be replaced by an actual value. For example:
 
-=begin code :allow<B>
-    The basic C<ln> command is: C<ln> B<R<source_file> R<target_file>>
-=end code
+The basic C<ln> command is: C<ln> R<source_file> R<target_file>
 
 or:
 
-=begin code :allow<B>
+=begin code :allow<R>
     Then enter your details at the prompt:
 
     =for input
-        Name: B<R<your surname>>
-          ID: B<R<your employee number>>
-        Pass: B<R<your 36-letter password>>
+        Name: R<your surname>
+          ID: R<your employee number>
+        Pass: R<your 36-letter password>
 =end code
 
 =head2 Terminal output