Adds more examples to the definition of ws

Thanks go  @jnthn for his clarification in StackOverflow. Closes #1729

doc/Language/grammars.pod6

@@ -225,9 +225,10 @@ Please bear in mind that we're preceding C<ws> with a dot to avoid capturing,
 which we are not interested in. Since in general whitespace is a separator, this
 is how it's mostly found.
 
-When C<rule> instead of C<token> is used, any whitespace after terms and closing
-parenthesis/brackets is turned into a non-capturing call to C<ws>,
-written as C«<.ws>» where C<.> means non-capturing. That is to say:
+When C<rule> instead of C<token> is used, C<:sigspace> is enabled by default and
+any whitespace after terms and closing parenthesis/brackets is turned into a
+non-capturing call to C<ws>, written as C«<.ws>» where C<.> means non-capturing.
+That is to say:
 
     rule entry { <key> '=' <value> }
 
@@ -246,6 +247,13 @@ You can also redefine the default C<ws> token:
         token ws { \h*   }
     }.parse: "4   \n\n 5"; # Fails
 
+And even capture it, but you need to use it explicitly:
+
+=for code
+grammar Foo { rule TOP {\d <ws> \d} };
+my $parsed = Foo.parse: "3 3";
+say $parsed<ws>; # OUTPUT: «｢｣␤»
+
 
 =head3 X«C<sym>|<sym>»