uxTaskBasePriorityGet reused the \defgroup id 'uxTaskPriorityGet'
already defined by uxTaskPriorityGet, only with a different title.
Doxygen reported:
task.h: warning: group uxTaskPriorityGet: ignoring title
"uxTaskBasePriorityGet" that does not match old title
"uxTaskPriorityGet"
Give uxTaskBasePriorityGet its own group id so both functions are
documented correctly.