The ornamental design for a syringecap, as shown and described.
FIG. 1 shows a perspective view of the invention;
FIG. 2 shows a top view of the invention;
FIG. 3 shows a front view of the invention; and,
FIG. 4 shows a bottom view of the invention.
The broken line showing in FIG. 4 is included for the purposes of illustrating and forms no part of the claimed design. The broken lines in FIGS. 1 and 2 which define the bounds of the claimed design form no part thereof.