"Delete all whitespace following a specified column in each line.
The left edge of the rectangle specifies the position in each line
at which whitespace deletion should begin. On each line in the
-rectangle, all continuous whitespace starting at that column is deleted.
+rectangle, all contiguous whitespace starting at that column is deleted.
When called from a program the rectangle's corners are START and END.
With a prefix (or a FILL) argument, also fill too short lines."