The ornamental design for a heatingdevice, as shown and described.
FIG. 1 is a perspective view of a heating device showing our new design;
FIG. 2 is a front elevational view of the heating device of FIG. 1;
FIG. 3 is a right side elevational view of the heating device of FIG. 1;
FIG. 4 is a bottom plan view of the heating device of FIG. 1;
FIG. 5 is an enlarged view of portion 5 in FIG. 1;
FIG. 6 is an enlarged view of portion 6 in FIG. 2; and,
FIG. 7 is an enlarged view of portion 7 in FIG. 1.
The evenly spaced broken lines shown in the drawings illustrate portions of the heating device that form no part of the claimed design. The dash-dot-dash broken lines identifying the enlarged views form no part of the claimed design.