The ornamental design for an ledlightbulb, as shown and described.
FIG. 1 is a front elevational view of an LED light bulb showing my new design;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a right side elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The structural features depicted by broken lines have been shown for the purpose of illustrating portions of the light that form no part of the claimed design.