Edit Ticker.h
Edit Ticker.h

Make minor copy edits to existing text.
mbedmicro/mbed,mbedmicro/mbed,andcor02/mbed-os,mbedmicro/mbed,andcor02/mbed-os,andcor02/mbed-os,kjbracey-arm/mbed,kjbracey-arm/mbed,kjbracey-arm/mbed,kjbracey-arm/mbed,mbedmicro/mbed,andcor02/mbed-os,andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed