inotify.7: Note that IN_ONLY_DIR can be used to avoid races

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man7/inotify.7

@@ -344,6 +344,8 @@ watch list.
 Only watch
 .I pathname
 if it is a directory.
+Using this flag provides an application with a race-free way of
+ensuring that the monitored objeect is a directory.
 .RE
 .PP
 The following bits may be set in the