adding a let as required by the Swift 3 compiler (kodecocodes#236)

Robert Gummesson · rayfix · commit f51f39b36ee7 · 2016-11-24T15:21:41.000-08:00
diff --git a/README.markdown b/README.markdown
@@ -568,7 +568,7 @@ var subview: UIView?
 var volume: Double?
 
 // later on...
-if let subview = subview, volume = volume {
+if let subview = subview, let volume = volume {
   // do something with unwrapped subview and volume
 }
 ```

Original file line number	Diff line number	Diff line change
`@@ -568,7 +568,7 @@ var subview: UIView?`
`568`	`568`	`var volume: Double?`
`569`	`569`
`570`	`570`	`// later on...`
`571`		`-if let subview = subview, volume = volume {`
	`571`	`+if let subview = subview, let volume = volume {`
`572`	`572`	`// do something with unwrapped subview and volume`
`573`	`573`	`}`
`574`	`574`	```