Previous perldeltas have been inconsistent with each other as to whether to
use L<> to C<> (but internally consistent). perldelta5140.pod uses L<>, which
is more useful, as it provides a direct link to fuller documentation at the
point where the reader is likely to want to follow it.
Switch the two existing entries from C<> to L<>, and update the perldelta
template to suggest L<>.
=item *
-XXX
+ [Verbatim block to avoid creating a bogus link]
+ L<XXX> has been upgraded from version 0.69 to version 0.70.
=back
=item *
-C<Math::Complex> has been upgraded from version 1.56 to version 1.57.
+L<Math::Complex> has been upgraded from version 1.56 to version 1.57.
Correct copy constructor usage.
Fix polarwise formatting with numeric format specifier.
=item *
-C<Time::HiRes> has been upgraded from version 1.9721_01 to version 1.9722.
+L<Time::HiRes> has been upgraded from version 1.9721_01 to version 1.9722.
Portability fix, and avoiding some compiler warnings.