The ornamental design for a haircurler, as shown and described.
FIG. 1 is a perspective view of a hair curler;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left elevational view thereof;
FIG. 5 is a right elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The evenly spaced broken lines illustrate the buttons, power connection, and interior bottom of the hair curler. None of the broken line disclosure forms part of the claimed design.