Remove old comment

The comment was introduced (in git) at commit
4be4c56239c224094e717dcd57068f58f99c2dfc ; it refers to a
FIXME located ~40 lines above it. The FIXME was removed in
dc8bc8e39230bde1eca569c564e65bf85c43de54.

lisp/org.el

@@ -19505,9 +19505,6 @@ because, in this case the deletion might narrow the column."
 (put 'org-self-insert-command 'pabbrev-expand-after-command t)
 (put 'orgtbl-self-insert-command 'pabbrev-expand-after-command t)
 
-;; How to do this: Measure non-white length of current string
-;; If equal to column width, we should realign.
-
 (defun org-remap (map &rest commands)
   "In MAP, remap the functions given in COMMANDS.
 COMMANDS is a list of alternating OLDDEF NEWDEF command names."