In the first example, use "mandoc -a" directly rather "mandoc -l".
It feels more natural to me to use -a directly when asking mandoc(1)
to use a pager. The reason that "mandoc -l" does exactly the same
as "mandoc -a" is that "mandoc" is essentially "man -lc", so the -a
implied by -l negates the -c and the -l has no effect because it is
already the default for mandoc(1).
The more usual command for doing the same is "man -l foo.1 bar.1 ..."
but that's off-topic for the mandoc(1) manual page.
Patch on tech@ from Anders Damsgaard <anders at adamsgaard dot dk>.