FIG. 1 is a front perspective of a weeder showing my new design; FIG. 2 is a front elevational view thereof; FIG. 3 is a back elevational view thereof; FIG. 4 is a left side elevational view thereof; FIG. 5 is a right side elevational view thereof; FIG. 6 is a top plan view thereof; and, FIG. 7 is a bottom plan view thereof. The matter displayed in dashed lines indicates context and does not form any part of the claimed design.