Add RETAIL to the list of adaptations

Under Requirements, delete all language following Retail NC/CI section:

Reference Guide updates:
Under Guidance for this credit for BDC and IDC, replace the following modifications for Retail:
There are no substantive changes to the prerequisite requirements; refer to the LEED v4 reference guide, with the following addition:
Beta Update
Retail projects should now follow guidance for New Construction/Commercial Interiors. Retail-specific requirements are no longer applicable.