tests: Fix comments of ToString() intervals
tests: Fix comments of ToString() intervals

Intervals were not correctly described.
Use scientific notation in comments consistent with code.

neutmute/UnitsNet,anjdreas/UnitsNet,maherkassim/UnitsNet,BrandonLWhite/UnitsNet,BoGrevyDynatest/UnitsNet,maherkassim/UnitsNet,BrandonLWhite/UnitsNet,Tirael/UnitsNet,anjdreas/UnitsNet