Fix Fix-it location

Author: DougGregor

test/Unsafe/safe.swift

@@ -140,7 +140,7 @@ func testKeyPath() {
 func takesAutoclosure<T>(_ body: @autoclosure () -> T) { }
 
 func testAutoclosure() {
-  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{20-20=unsafe }}
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{3-3=unsafe }}
   takesAutoclosure(unsafeFunction()) // expected-note{{reference to unsafe global function 'unsafeFunction()'}}
 
   unsafe takesAutoclosure(unsafeFunction())