Add LT3756xMSE buck/boost/sepic 100V LED driver

Created by: MatthewStephenson

Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/375612fb.pdf

This is a straight copy of the existing symbol for the pin-compatible LT3755xMSE, with the relevant data fields changed.

Rule 4.4 will fail the travis checks because VREF is actually an output on this chip.