The ornamental design for tongs, as shown and described.
FIG. 1 is a top, front, and left side perspective view of tongs according to our design;
FIG. 2 is a bottom, front, and left side perspective view thereof;
FIG. 3 is a left side elevation view thereof;
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a rear elevation view thereof; and,
FIG. 8 is front elevation view thereof.
Throughout the Figures, where shown, (i) the dashed lines showing additional structure of the tongs depict environment and form no part of the claimed design, and (ii) the dotted/dashed lines illustrate unclaimed boundaries of surfaces claimed as part of the design.