Removes all references to synopsis... but one

Which probably makes sense since it speaks about what options were
going to be removed. Closes #2225

doc/Language/5to6-nutshell.pod6

@@ -204,13 +204,12 @@ my @books = $xml
 
 =end item
 
-However, note that you can use L<unspace|https://design.perl6.org/S02.html#Unspaces>
+However, note that you can use L<unspace|/language/syntax#Unspace>
 to add whitespace in Perl 6 code in places where it is otherwise not
 allowed.
 
-See also L<S03#Minimal whitespace DWIMmery|https://design.perl6.org/S03.html#Minimal_whitespace_DWIMmery> and
-L<S04#Statement parsing|https://design.perl6.org/S04.html#Statement_parsing>
-in the Perl 6 design docs.
+See also L<other lexical conventions in the syntax
+page|https://docs.perl6.org/language/syntax#Lexical_conventions>.
 
 =head2 Sigils