Change three occurences of `lonCorrection` into `lngCorrection` in a class, to correct a tiny style inconsistency introduced by the last commit to the class two years ago

[kenneth-kho]

Summary

The last commit to https://github.com/googlemaps/android-maps-utils/blob/main/library/src/main/java/com/google/maps/android/PolyUtil.java introduced a tiny style inconsistency.

I just want to change three occurences of lonCorrection into lngCorrection, because the rest of the class uses lat lng instead of lat lon.