Add that over2 and wrap need a Newtype instance of Complex. (#278)

* Add that over2 and wrap need a Newtype instance of Complex.

* Quick do intead of to typo fix

Co-authored-by: milesfrain <[email protected]>

Author: shaunplee

text/chapter6.md

@@ -314,7 +314,7 @@ Many standard type classes come with their own set of similar laws. The laws giv
 
 ### Deriving Instances
 
-Rather than writing instances manually, you can let the compiler to most of the work for you. Take a look at this [Type Class Deriving guide](https://github.com/purescript/documentation/blob/master/guides/Type-Class-Deriving.md). That information will help you solve the following exercises.
+Rather than writing instances manually, you can let the compiler do most of the work for you. Take a look at this [Type Class Deriving guide](https://github.com/purescript/documentation/blob/master/guides/Type-Class-Deriving.md). That information will help you solve the following exercises.
 
 ## Exercises
 
@@ -332,7 +332,7 @@ newtype Complex
 
 2. (Easy) Derive an `Eq` instance for `Complex`. _Note_: You may instead write this instance manually, but why do more work if you don't have to?
 
-3. (Medium) Define a `Semiring` instance for `Complex`. _Note_: You can use `wrap` and `over2` from [`Data.Newtype`](https://pursuit.purescript.org/packages/purescript-newtype/docs/Data.Newtype) to create a more concise solution.
+3. (Medium) Define a `Semiring` instance for `Complex`. _Note_: You can use `wrap` and `over2` from [`Data.Newtype`](https://pursuit.purescript.org/packages/purescript-newtype/docs/Data.Newtype) to create a more concise solution. If you do so, you will also need to import `class Newtype` from `Data.Newtype` and derive a `Newtype` instance for `Complex`.
 
 4. (Easy) Derive (via `newtype`) a `Ring` instance for `Complex`. _Note_: You may instead write this instance manually, but that's not as convenient.