[io grant] Document IO::Handle.nl-out attribute

Author: zoffixznet

doc/Type/IO/Handle.pod6

@@ -653,6 +653,29 @@ L«C<lines>|/routine/lines».
     }
 =end code
 
+=head2 method nl-out
+
+Defined as:
+
+    has Str:D $.nl-out is rw = "\n";
+
+One of the attributes that can be set via C<.new> or L<open>.
+Defaults to C<"\n">. Takes a L<Str> specifying output line ending for this
+handle, to be used by methods L«C<.put>|/type/IO::Handle#method_put»
+and L«C<.say>|/type/IO::Handle#method_say».
+
+=begin code :skip-test
+    with 'test'.IO {
+        given .open: :w {
+            .put: 42;
+            .nl-out = 'foo';
+            .put: 42;
+            .close;
+        }
+        .slurp.perl.say; # OUTPUT: «"42\n42foo"»
+    }
+=end code
+
 =head2 method opened
 
 Defined as: