Update 1987/biggar/README.md about missing note

There is supposed to be a comment from the judges in 1987/wall/README.md
about 1987/biggar's entry but it appears to be missing. Rather than
delete the comment in 1987/biggar we note that it was originally there
but has gone missing.

1987/biggar/README.md

@@ -33,7 +33,10 @@ One vendor's lint got hung in an infinite loop over this entry!
 > FYI:  We will let Mark get away with this truly sick entry this time, but 
 > for the future on we have placed a limit on the size of a compile line.
 
-Also see our comment in [Larry Wall's entry](../wall/README.md) regarding Mark's contribution.
+NOTE: originally there we made a comment in [Larry Wall's
+entry](../wall/README.md) regarding Mark's contribution but it seems to have
+been lost in time. If anyone knows about its whereabouts we'd appreciate letting
+us know. Thanks!
 
 ## Judges' comments: