I claim the ornamental design for a visor, as shown and described.
FIG. 1 is a front perspective view of the visor.
FIG. 2 is a rear perspective view of the visor.
FIG. 3 is a front perspective view of the visor in use.
FIG. 4 is a side view of the visor in use; and,
FIG. 5 is a top plan view of the visor in a flattened state.
The broken lines showing a person in FIG. 3 illustrate the claimed design while in use, and form no part thereof. The broken lines in FIG. 5 are fold lines.