[Swift] Adds a format file and reformats the swift project (#6250)

* Formats files & adds licence

* Revert arrays

* Keeps array indentation as is

* Adds licence to code formatter

* Updates code generators

swift/Sources/FlatBuffers/Struct.swift

@@ -1,16 +1,32 @@
+/*
+ * Copyright 2020 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 import Foundation
 
 public struct Struct {
-    public private(set) var bb: ByteBuffer
-    public private(set) var postion: Int32
-    
-    public init(bb: ByteBuffer, position: Int32 = 0) {
-        self.bb = bb
-        self.postion = position
-    }
-    
-    public func readBuffer<T: Scalar>(of type: T.Type, at o: Int32) -> T {
-        let r = bb.read(def: T.self, position: Int(o + postion))
-        return r
-    }
+  public private(set) var bb: ByteBuffer
+  public private(set) var postion: Int32
+
+  public init(bb: ByteBuffer, position: Int32 = 0) {
+    self.bb = bb
+    postion = position
+  }
+
+  public func readBuffer<T: Scalar>(of type: T.Type, at o: Int32) -> T {
+    let r = bb.read(def: T.self, position: Int(o + postion))
+    return r
+  }
 }