Clarify Adding Workout to Routine

[ShanBell42]

I submitted this issue in the wger repository, not realizing that this repo was where I should have suggested it.

When adding a new workout to a day under a Routine, a user could have some confusion about where to add that information. Adding a hover tooltip to the add button would help the user know what action they are taking instead of assuming it is the correct thing.

I intend to submit a pull request for this issue, but please let me know if there is another process I should be following instead.