The ornamental design for a visor, as shown and described.
FIG. 1 is a first perspective view of the visor of this invention;
FIG. 2 is a front elevation view of the visor;
FIG. 3 is a top plan view of the visor;
FIG. 4 is a rear elevation view of the visor;
FIG. 5 is a first side elevation view of the visor;
FIG. 6 is a second side elevation view of the visor; and,
FIG. 7 is a bottom plan view of the visor.
The broken lines on the top surface of the visor depicting a logo, as well as the areas between the broken lines, illustrate portions of the visor that are not claimed.