The ornamental design for a firearmtrigger, as shown and described.
FIG. 1 is a front-right angled view of a firearm trigger, showing the new design.
FIG. 2 is a right-rear angled view thereof.
FIG. 3 is a front view thereof.
FIG. 4 is a back view thereof.
FIG. 5 is a right-side view thereof.
FIG. 6 is a left-side view thereof.
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The broken lines in the Figures depict unclaimed portions of the device and are for illustrative purposes only. The broken lines form no part of the claimed design.