Revise self-serve release docs to match jobs

Adjust formatting of the trigger file path default value
for container, maven and PyPI release jobs.  Drop the
parameter from release job docs to match the template,
and add a sentence with the regular expression.

Change-Id: Ibff31ac5c82fc1ed4f025fb4c16d9c907456f3c8
Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>