sections multiple times. This started to happen because, pmdoc_Sh(), the handler function
responsible for parsing the Sh macros, used to recursively go through all the child
nodes and then the next nodes starting from top level Sh block node.
Now, once it has processed all the child nodes of the top level block node,
it moves to the next node, which is the top level block node of the next section and
in this way one call to pmdoc_Sh() was causing a complete pass through the
man page. Since, mandoc(3) calls pmdoc_Sh() for each .Sh macro in the man
page, it would result in parsing some of the sections multiple times.
This never happened with the previous versions of mandoc, so we never noticed.
I've fixed this by starting the parse sequence of the Sh macro from its body, which gurantees
that we will stop once that section ends.
ok christos@
150a47b73e