Remove unneeded description text on Participant

[larssandergreen]

Overview

Cleanup of extraneous descriptions on Participant, including Price Set via change selections. Some minor formatting clean up.

Before

On Change Selections

After

On Change Selections (still broken, but at least the formatting is better)

[civibot]

(Standard links)

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[aydun]

All seem sensible changes

[larssandergreen]

Thanks @aydun!