The ornamental design for a shirtstay with socketfastener, as shown and described.
FIG. 1 is a front perspective view of a shirt stay with socket fastener, showing our new design;
FIG. 2 is a back perspective view thereof;
FIG. 3 is a back side elevation view thereof;
FIG. 4 is a front side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a left side elevation view thereof;
FIG. 7 is an enlarged top side plan view thereof; and,
FIG. 8 is an enlarged bottom side plan view thereof.
The separation and a small bracket depicted in FIGS. 1-6 is utilized to indicate a symbolic break in the claimed design. The bracket and portions between the breaks that are not shown form no part thereof.