tail: adjust help/usage texts

Signed-off-by: Cristian Ionescu-Idbohrn <cristian.ionescu-idbohrn@axis.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/Config.src b/coreutils/Config.src
index 0c44c4b..33defa4 100644
--- a/coreutils/Config.src
+++ b/coreutils/Config.src
@@ -633,12 +633,13 @@
 	default y
 	depends on TAIL
 	help
-	  The options (-q, -s, and -v) are provided by GNU tail, but
+	  The options (-q, -s, -v and -F) are provided by GNU tail, but
 	  are not specific in the SUSv3 standard.
 
 	    -q      Never output headers giving file names
 	    -s SEC  Wait SEC seconds between reads with -f
 	    -v      Always output headers giving file names
+	    -F      Same as -f, but keep retrying
 
 config TEE
 	bool "tee"