The ornamental design for a fitting, as shown and described.
FIG. 1 is a top plan view of a fitting showing my new design therefor, the portions shown in broken lines forming no part of the design;
FIG. 2 is a front elevational view thereof, the rear elevational view being identical;
FIG. 3 is a left side view thereof, the right side view being identical to FIG. 1, the portions shown in broken lines forming no part of the design; and,