The ornamental design for a gutter, as shown and described.
FIG. 1 is a front perspective view of a gutter in accordance with my new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a left side elevational view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a rear elevational view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a top pan view thereof; and,
FIG. 8 is a front elevational view thereof.
FIGS. 1-2 and 5-8 show the end of the gutter with a symbolic break in its length. The appearance of any portion of the article beyond the break forms no part of the claim.