Fix a typo in 03_ticket_v1/08_stack (#19)

The type argument of `size_of` is `<u8>` instead of `<String>`.

book/src/02_basic_calculator/06_while.md

@@ -30,7 +30,7 @@ while i <= 5 {
 }
 ```
 
-This will keep adding 1 to `sum` until `i` is no longer less than or equal to 5.
+This will keep adding 1 to `i` and `i` to `sum` until `i` is no longer less than or equal to 5.
 
 ## The `mut` keyword
 

book/src/03_ticket_v1/08_stack.md

@@ -45,7 +45,7 @@ using the [`std::mem::size_of`](https://doc.rust-lang.org/std/mem/fn.size_of.htm
 For a `u8`, for example:
 
 ```rust
-// We'll explain this funny-looking syntax (`::<String>`) later on.
+// We'll explain this funny-looking syntax (`::<u8>`) later on.
 // Ignore it for now.
 assert_eq!(std::mem::size_of::<u8>(), 1);
 ```

book/src/04_traits/08_from.md

@@ -105,7 +105,7 @@ though the former bound is implicit.
 
 In [`std`'s documentation](https://doc.rust-lang.org/std/convert/trait.From.html#implementors) 
 you can see which `std` types implement the `From` trait.  
-You'll find that `&str` implements `From<&str> for String`. Thus, we can write:
+You'll find that `String` implements `From<&str> for String`. Thus, we can write:
 
 ```rust
 let title = String::from("A title");
@@ -129,7 +129,7 @@ where
 }
 ```
 
-If a type `T` implements `From<U>`, then `Into<U> for T` is automatically implemented. That's why
+If a type `U` implements `From<T>`, then `Into<U> for T` is automatically implemented. That's why
 we can write `let title = "A title".into();`.
 
 ## `.into()`

book/src/04_traits/10_clone.md

@@ -75,7 +75,7 @@ Heap:  | H | e | l | l | o |
 When `let t = s.clone()` is executed, a whole new region is allocated on the heap to store a copy of the data:
 
 ```text
-                    s                                    s
+                    s                                    t
       +---------+--------+----------+      +---------+--------+----------+
 Stack | pointer | length | capacity |      | pointer | length | capacity |
       |  |      |   5    |    5     |      |  |      |   5    |    5     |

exercises/04_traits/08_from/src/lib.rs

@@ -1,4 +1,4 @@
-// TODO: Implement the `From` trait for the `u32` type to make `example` compile.
+// TODO: Implement the `From` trait for the `WrappingU32` type to make `example` compile.
 
 pub struct WrappingU32 {
     value: u32,

exercises/05_ticket_v2/09_error_trait/src/lib.rs

@@ -11,7 +11,7 @@ enum TicketNewError {
 // TODO: `easy_ticket` should panic when the title is invalid, using the error message
 //   stored inside the relevant variant of the `TicketNewError` enum.
 //   When the description is invalid, instead, it should use a default description:
-//   "No description provided".
+//   "Description not provided".
 fn easy_ticket(title: String, description: String, status: Status) -> Ticket {
     todo!()
 }