The ornamental designs for armrest, as shown and described.
FIG. 1 is a rear perspective view of our designs;
FIG. 2 is a left side view, which is a mirror image of a right side view;
FIG. 3 is a top view;
FIG. 4 is a bottom view;
FIG. 5 is a front view, which is enlarged for clarity; and,
FIG. 6 is a back view, which is enlarged for clarity.
The dashed lines in the figures form no part of the claimed designs. A dash-dot line in a figure is a boundary that the design depicted in the figure extends to, but does not include. Surface shading in the figures is provided solely to indicate contour. All other surface(s) or portion(s) of our armrest not shown in the figures or otherwise described in the specification form no part of the claimed designs.
In other embodiments of our designs, dashed line(s) indicating any unclaimed feature(s) may be replaced with solid line(s) to claim those feature(s), solid line(s) indicating any claimed feature(s) may be replaced with dashed line(s) so as not to claim those feature(s), and/or dash-dot line(s) indicating boundar(ies) may be deleted.