log.html: Add (non-critical) to header of a non-critical test case leaf
log.html: Add (non-critical) to header of a non-critical test case leaf

This is to help users identify the test cases that are non-critical - and ignore them.
Non-critical test cases that fail are closed by default.

Senseg/robotframework,Senseg/robotframework,Senseg/robotframework,Senseg/robotframework,Senseg/robotframework,userzimmermann/robotframework-python3,userzimmermann/robotframework-python3,userzimmermann/robotframework-python3,userzimmermann/robotframework-python3,userzimmermann/robotframework-python3