Document max_connections somewhat

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@4238 d4fa192b-c00b-0410-8231-f00ffab90ce4

man/vcl.7so

@@ -93,6 +93,11 @@ if (req.http.host ~ "^(www\.)?example.com$") {
 }
 .Ed
 .Pp
+To avoid overloading backend servers,
+.Fa .max_connections
+can be set to limit the maximum number of concurrent backend connections.
+.Ed
+.Pp
 The timeout parameters can be overridden in the backend declaration.
 The timeout parameters are
 .Fa .connect_timeout