Fix some thinkos in --with-editor and --with-env-editor descriptions.

Noticed by Norihiko Murase.

INSTALL

@@ -493,20 +493,20 @@ The following options are also configurable at runtime:
 	Don't print the lecture the first time a user runs sudo.
 
   --with-editor=PATH
-	Specify the default editor path for use by visudo.  This may be
-	a single pathname or a colon-separated list of editors.  In
-	the latter case, visudo will choose the editor that matches
-	the user's USER environment variable or the first editor in
-	the list that exists.  The default is the path to vi on your system.
+	Specify the default editor path for use by visudo.  This may be a
+	single pathname or a colon-separated list of editors.  In the latter
+	case, visudo will choose the editor that matches the user's VISUAL
+	or EDITOR environment variables or the first editor in the list that
+	exists.  The default is the path to vi on your system.
 
   --with-env-editor
-	Makes visudo consult the EDITOR and VISUAL environment variables before
+	Makes visudo consult the VISUAL and EDITOR environment variables before
 	falling back on the default editor list (as specified by --with-editor).
 	Note that this may create a security hole as it allows the user to
 	run any arbitrary command as root without logging.  A safer alternative
-	is to use a colon-separated list of editors with the --with-env-editor
-	option.  visudo will then only use the EDITOR or VISUAL if they match
-	a value specified via --with-editor.
+	is to use a colon-separated list of editors with the --with-editor
+	option.  visudo will then only use the VISUAL or EDITOR variables
+	if they match a value specified via --with-editor.
 
   --disable-authentication
         By default, sudo requires the user to authenticate via a