The ornamental design for a digital displaysolderingiron, as shown and described.
FIG. 1 is a perspective view of a digital display soldering iron showing my new design;
FIG. 2 is another perspective view thereof;
FIG. 3 is a front elevational view thereof,
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof;
FIG. 9 is an enlarged view of the left side elevational view shown in FIG. 5; and,
FIG. 10 is an enlarged view of the right side elevational view shown in FIG. 6.
The broken lines depict portions of the digital display soldering iron in which the design is embodied that are not considered part of the claimed design.