Fixed guard else condition formatting…no functional changes.

Source/MultipartFormData.swift

@@ -257,8 +257,7 @@ open class MultipartFormData {
         var isDirectory: ObjCBool = false
         let path = fileURL.path
 
-        guard FileManager.default.fileExists(atPath: path, isDirectory: &isDirectory) && !isDirectory.boolValue else
-        {
+        guard FileManager.default.fileExists(atPath: path, isDirectory: &isDirectory) && !isDirectory.boolValue else {
             setBodyPartError(withReason: .bodyPartFileIsDirectory(at: fileURL))
             return
         }