Log Message:
lowdown: update to 0.6.5.

ChangeLog:

Version 0.6.5, 2020-05-20

- Fix an off-by-one where smarty-pants would be applied to some terms not
  on a word boundary. For example, 1/40 was erroneously construed as 1/4
  then a zero.

- Use pkg-config(1) for the installed library and improve the documentation.