The ornamental design for a drinkingstraw, as shown and described.
FIG. 1 is a left-side perspective view of a drinking straw showing my new design;
FIG. 2 is a front perspective view thereof;
FIG. 3 is a top end view thereof;
FIG. 4 is a left-side elevation view thereof;
FIG. 5 is a left-side partial view taken along line 5-5 of FIG. 1; and,
FIG. 6 is a front partial view taken along line 6-6 of FIG. 2.
The right-side perspective view is a mirror image of the left-side. The rear perspective view thereof is a mirror image of the front perspective view. The bottom end view thereof is a mirror image of the top end view.