Fix: doc: escape double quote in bt_p alias

Fix: doc: escape double quote in bt_p alias

The HTML doc shows some `<span class=` where the parameter names are
meant to appear.  Escape those double quotes to fix it.

The output was correct in the past, it only started to display the wrong
thing with this commit, in Doxygen 1.9.0:

https://github.com/doxygen/doxygen/commit/eb3d1eb5ad85c94d6f2c32934fce2b8630331d6c

Reported-By: Brice Videau <bvideau@anl.gov>
Change-Id: I61f3b557e3d8bf1428dd57e4c1ce950461e32479
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/11647
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>