The ornamental design of a candleholder, as shown and described.
FIG. 1 is a right perspective view of a candle holder in accordance with the present invention;
FIG. 2 is a right side view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The evenly spaced, evenly dashed broken lines in the drawings showing the candle holder illustrate the portions of the candle holder that form no part of the claimed design. The dash-dot-dash broken lines in the drawings depict an environmental candle only and forms no part of the claimed design.