Uniquify headlines in S22 to work around a rendering bug in design.pe…

…rl6.org

The renderer seems to add the contents of the completely separate "bin"
sections.

S22-package-format.pod

@@ -293,14 +293,14 @@ Dependencies need not be Perl 6 only. By using the C<:from> adverb on the C<use>
 string, dependencies external to Perl 6 can be specified. These could be Perl 5
 modules like C<Mojolicious:from<Perl5>>. Two names are reserved:
 
-=head4 bin
+=head4 :from<bin>
 
 With C<curl:from<bin>> one can specify on a C<curl> executable be available at
 the given stage. The installer may only check the availability of this dependency,
 or it may try to provide this, e.g. by installing the appropriate package to the
 system.
 
-=head4 native
+=head4 :from<native>
 
 A dependency like C<curl:from<native>> tells the installer, that the system
 library with the given name must be present. The name is expanded following the