Update Episode 6’s Exercises page to match transcript. (#31)

0006-functional-setters/Functional Setters.playground/Pages/02-Exercises.xcplaygroundpage/Contents.swift

@@ -5,32 +5,42 @@
  */
 // TODO
 /*:
- 2. Take the following `User` struct and write a setter for its `name` property. Add another property, and add a setter for it. What are some potential issues with building these setters?
- */
+ 2. Take a `struct`, _e.g._:
+
+```
 struct User {
   let name: String
 }
+```
+
+ Write a setter for its property. Take (or add) another property, and add a setter for it. What are some potential issues with building these setters?
+ */
 // TODO
 /*:
- 3. Add a `location` property to `User`, which holds a `Location`, defined below. Write a setter for `userLocationName`. Now write setters for `userLocation` and `locationName`. How do these setters compose?
- */
+ 3. Take a `struct` with a nested `struct`, _e.g._:
+
+```
 struct Location {
   let name: String
 }
-// TODO
-/*:
- 4. Do `first` and `second` work with tuples of three or more values? Can we write `first`, `second`, `third`, and `nth` for tuples of _n_ values?
+
+struct User {
+  let location: Location
+}
+```
+
+ Write a setter for `userLocationName`. Now write setters for `userLocation` and `locationName`. How do these setters compose?
  */
 // TODO
 /*:
- 5. Write a setter for a dictionary that traverses into a key to set a value.
+ 4. Do `first` and `second` work with tuples of three or more values? Can we write `first`, `second`,`third`, and `nth` for tuples of _n_ values?
  */
 // TODO
 /*:
- 6. Write a setter for a dictionary that traverses into a key to set a value if and only if that value already exists.
+ 5. Write a setter for a dictionary that traverses into a key to set a value.
  */
 // TODO
 /*:
- 7. What is the difference between a function of the form `((A) -> B) -> (C) -> (D)` and one of the form `(A) -> (B) -> (C) -> D`?
+ 6. What is the difference between a function of the form `((A) -> B) -> (C) -> (D)` and one of the form `(A) -> (B) -> (C) -> D`?
  */
 // TODO