The ornamental design for an alignmenttool, as shown and described.
FIG. 1 is a perspective view of an alignment tool according to oar new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a right, side view thereof;
FIG. 5 is a left, side view thereof;
FIG. 6 is a lop plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken-line showing of portions of the tool is included for the purpose of illustrating environmental structure and forms no part of the claimed design.