The ornamental design for a fitting, as shown and described.
FIG. 1 is a left view of the fitting showing my new design therefor;
FIG. 2 is a front elevational view thereof, the rear elevational view being identical;
FIG. 3 is a top plan view thereof, the bottom plan view being identical to FIG. 1, the portions shown in broken lines forming no part of the design; and,
FIG. 4 is a right side view thereof, the portions shown in broken lines forming no part of the design.