An unsigned value can never be less than 0

Defect 76764 (STATIC_C)
Checker NO_EFFECT (subcategory unsigned_compare_macros)
File: /src/mongo/util/itoa.cpp
Function mongo::ItoA::ItoA(unsigned int)
/src/mongo/util/itoa.cpp, line: 1060
This greater-than-or-equal-to-zero comparison of an unsigned value is always true. "pos >= 0UL".

            invariant(pos >= 0);