Make pseudocode block tags consistent

They are all now [source,c++] and use ---- as the
delimiter.

Also made the pseudocode indentation consistent (4 spaces)
in the introduction sections.

Signed-off-by: Eric Kunze <eric.kunze@arm.com>
Change-Id: I1287a60cfeae8b7e3c63b9fc8885b1ebf3d3386d