Fix Dumbbell P/P/L script

[brianstrauch]

The source for this routine can be found here and says:

Add Hanging Leg Raises to the end of every other workout

This PR doubles the schedule across 6 days to include Hanging Leg Raises at the end of every other workout instead of on days 1 and 3. The new pattern for Hanging Leg Raises is as follows:

Push: Yes
Pull: No
Legs: Yes
Push: No
Pull: Yes
Legs: No

On day 7, the cycle starts again.