I claim the ornamental design for a chair, as shown and described.
FIG. 1 is a top, front, left perspective view of an embodiment of the claimed design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left elevation view thereof;
FIG. 5 is a right elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines in the drawings form no part of the claimed design. Broken lines formed by equal length dashes show unclaimed subject matter. Broken lines formed of unequal length dashes (i.e., dash-dot) define bounds of the claimed design. Broken away symbols having a jagged element show that no particular length of the portion is claimed.