The ornamental design for an adapter for connector, as shown and described.
FIG. 1 is a front-top-right perspective view of an adapter for connector showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a right side thereof;
FIG. 5 is a left side thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a front-bottom-left perspective view thereof.
The broken lines depicting the remainder of the adapter for connector show features that form no part of the claimed design. The unshaded internal walls form no part of the claimed design.