Fix documentation

Author: mhegazy

src/lib/es6.d.ts

@@ -125,34 +125,34 @@ interface ObjectConstructor {
  * Copy the values of all of the enumerable own properties from one or more source objects to a 
  * target object. Returns the target object.
  * @param target The target object to copy to.
- * @param source source objects to copy properties from.
+ * @param source The source object from which to copy properties.
  */
  assign<T, U>(target: T, source: U): T & U;
 
  /**
  * Copy the values of all of the enumerable own properties from one or more source objects to a 
  * target object. Returns the target object.
  * @param target The target object to copy to.
- * @param source1 first source objects to copy properties from.
- * @param source2 second source objects to copy properties from.
+ * @param source1 The first source object from which to copy properties.
+ * @param source2 The second source object from which to copy properties.
  */
  assign<T, U, V>(target: T, source1: U, source2: V): T & U & V;
 
  /**
  * Copy the values of all of the enumerable own properties from one or more source objects to a 
  * target object. Returns the target object.
  * @param target The target object to copy to.
- * @param source1 first source objects to copy properties from.
- * @param source2 second source objects to copy properties from.
- * @param source3 second source objects to copy properties from.
+ * @param source1 The first source object from which to copy properties.
+ * @param source2 The second source object from which to copy properties.
+ * @param source3 The third source object from which to copy properties.
  */
  assign<T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W;
 
  /**
  * Copy the values of all of the enumerable own properties from one or more source objects to a 
  * target object. Returns the target object.
  * @param target The target object to copy to.
- * @param sources One or more source objects to copy properties from.
+ * @param sources One or more source objects from which to copy properties
  */
  assign(target: any, ...sources: any[]): any;