style: Change include sorter to yield one line at a time

style: Change include sorter to yield one line at a time

The include sorter class normally yields one string per line and
relies on the caller to merge lines into a block of text separated by
newlines. However, there are cases when this isn't true. This makes
diffing using Python's difflib hard. This changeset updates the
include sorter to never do this and always yield one line at a time.

Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Steve Reinhardt <steve.reinhardt@amd.com>
--HG--
extra : rebase_source : 154c9c7e1ebdd77e09fe5f28d0cfddc9e6c6b1eb