This reverts a previous change where line_no was removed and put into
a triple tuple. It was discovered that re.Match.span() conveniently
returns (start, end), so separating line_no again makes the code cleaner.
The legibility of the code heavily outweighs the issues pointed out by
Pylint (hence disabled).
Signed-off-by: Yuto Takano <yuto.takano@arm.com>