hier(7) - remove excessive whitespace

[trasz]

Summary

Remove excessive horizontal whitespace from hier(7) by fixing usage
of "-width". The http://mdocml.bsd.lv/mdoc/details/width.html says:
"Do not use macros in the argument specifying the width, that's not
portable. While GNU troff can handle it, mandoc cannot." The same
problem seems to exist in many other man pages.