The ornamental design for a hearingaid, as shown and described.
1. Hearing Aid
1.1 : Perspective
1.2 : Top
1.3 : Bottom
1.4 : Right
1.5 : Left
1.6 : Front
1.7 : Back
Fig. 1.1 is a front and right side perspective view of a hearing aid showing our new design; fig. 1.2 is a top view thereof; fig. 1.3 is a bottom view thereof; fig. 1.4 is a right side view thereof; fig. 1.5 is a left side view thereof; fig. 1.6 is a front side view thereof; and fig. 1.7 is a rear side view thereof.
The broken lines depict portions of the hearing aid that form no part of the claimed design.