NEWS: quote false [ci skip]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64446 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

NEWS

@@ -121,7 +121,7 @@ sufficient information, see the ChangeLog file or Redmine
 
     * incompatible changes:
         * `system()` and `exec()` do not close non-standard file descriptors
-          (The default of `:close_others` option is changed to false by
+          (The default of `:close_others` option is changed to `false` by
           default.  but we still set the `FD_CLOEXEC` flag on descriptors we
           create).  [Misc #14907]