Minor formatting cleanup: Remove trailing blanks on lines
Minor formatting cleanup: Remove trailing blanks on lines

Trailing blanks on a line are not visible, and that can cause
long-term problems.  Remove all trailing blanks in set.mm.

Signed-off-by: David A. Wheeler <9ae72d22d8b894b865a7a496af4fab6320e6abb2@dwheeler.com>

metamath/set.mm,metamath/set.mm,metamath/set.mm