doc/man: make default values of boolean init. params. clearer

doc/man: make default values of boolean init. params. clearer

This patch answers to <https://bugs.lttng.org/issues/1387>, removing the
"=`yes`" and "=`no`" in the component class manual pages to replace them
with "='VAL'" and indicate the behaviour depending on "'VAL'", as well
as the default value.

Fixes: https://bugs.lttng.org/issues/1387
Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Change-Id: Ie7439fa397e2a9a5818152a68073f7bf87385675
Reviewed-on: https://review.lttng.org/c/babeltrace/+/10709
(cherry picked from commit 6f6e5e6146d1d55f9d49b587a64e2b32ebc29064)
Reviewed-on: https://review.lttng.org/c/babeltrace/+/10726