The ornamental design for a wine decanting funnel, as shown and described.
FIG. 1 is a perspective view of the wine decanting funnel showing our new design;
FIG. 2 is a side elevational view of FIG. 1;
FIG. 3 is a top plan view of FIG. 1; and,
FIG. 4 is a bottom plan view of FIG. 1.
The broken line showings in FIGS. 1 through 4 are for illustrative purposes only, depicting the environment and/or functional components of the new design, forming no part thereof as claimed.