The [default] argument is used for setting the default highlighting for a group. If highlighting has already been specified for the group the command will be ignored. Also when there is an existing link.
This patch makes jumps go the the first/last hunk when the given count
was bigger than the available hunks.
E.g. when there are only 2 hunks and you use 4]c, the cursor jumps to
the last hunk nevertheless. Before this patch the cursor wouldn't move
at all (which mimics the standard behaviour of ]c/[c).
Closes#41.