The ornamental design for a fabric, as shown and described.
FIG. 1 is a front view of a fabric according to my design;
FIG. 2 is a duplicate view of the design of FIG. 1 showing areas of details;
FIG. 3 is an enlarged detail view of area 3 circumscribed by broken lines in FIG. 2; and,
FIG. 4 is an enlarged detail view of area 4 circumscribed by broken lines in FIG. 2.
The broken lines forming a perimeter around the fabric in FIGS. 1 and 2 depict the boundaries to the claim and forms no part thereof. The broken lines within FIG. 2 and surrounding FIGS. 3 and 4 denote the boundaries of the areas of the details and form no part of the claimed design.