Duration doc: s/format use/format using/
Parse doc: ", or when" -> "or, when"

Maybe the format template should put 01/02 3:04:05pm '06 -0700 in an
indented line like the other date.  People have reported skimming and seeing
only the date(1)-format line and missing the important note about 1-2-3.

Also it would be nice if the format could be moved somewhere that is easier
to find with godoc.  When I need to remind myself what the date is, I never
know what to ask godoc for inside package time, and I end up skimming through
the whole 'godoc time' output.  Maybe 'godoc time Parse'?