Misc book improvements

src/doc/trpl/closures.md

@@ -33,8 +33,8 @@ let plus_two = |x| {
 assert_eq!(4, plus_two(2));
 ```
 
-You’ll notice a few things about closures that are a bit different than regular
-functions defined with `fn`. The first of which is that we did not need to
+You’ll notice a few things about closures that are a bit different from regular
+functions defined with `fn`. The first is that we did not need to
 annotate the types of arguments the closure takes or the values it returns. We
 can:
 
@@ -48,18 +48,18 @@ But we don’t have to. Why is this? Basically, it was chosen for ergonomic reas
 While specifying the full type for named functions is helpful with things like
 documentation and type inference, the types of closures are rarely documented
 since they’re anonymous, and they don’t cause the kinds of error-at-a-distance
-that inferring named function types can.
+problems that inferring named function types can.
 
 The second is that the syntax is similar, but a bit different. I’ve added spaces
-here to make them look a little closer:
+here for easier comparison:
 
 ```rust
 fn  plus_one_v1   (x: i32) -> i32 { x + 1 }
 let plus_one_v2 = |x: i32| -> i32 { x + 1 };
 let plus_one_v3 = |x: i32|          x + 1  ;
 ```
 
-Small differences, but they’re similar in ways.
+Small differences, but they’re similar.
 
 # Closures and their environment
 
@@ -99,7 +99,7 @@ note: previous borrow ends here
 fn main() {
     let mut num = 5;
     let plus_num = |x| x + num;
-    
+
     let y = &mut num;
 }
 ^
@@ -161,7 +161,7 @@ of `num`. So what’s the difference?
 ```rust
 let mut num = 5;
 
-{ 
+{
     let mut add_num = |x: i32| num += x;
 
     add_num(5);
@@ -180,7 +180,7 @@ If we change to a `move` closure, it’s different:
 ```rust
 let mut num = 5;
 
-{ 
+{
     let mut add_num = move |x: i32| num += x;
 
     add_num(5);

src/doc/trpl/trait-objects.md

@@ -261,7 +261,7 @@ static Foo_for_String_vtable: FooVtable = FooVtable {
 ```
 
 The `destructor` field in each vtable points to a function that will clean up
-any resources of the vtable’s type, for `u8` it is trivial, but for `String` it
+any resources of the vtable’s type: for `u8` it is trivial, but for `String` it
 will free the memory. This is necessary for owning trait objects like
 `Box<Foo>`, which need to clean-up both the `Box` allocation as well as the
 internal type when they go out of scope. The `size` and `align` fields store
@@ -270,7 +270,7 @@ essentially unused at the moment since the information is embedded in the
 destructor, but will be used in the future, as trait objects are progressively
 made more flexible.
 
-Suppose we’ve got some values that implement `Foo`, then the explicit form of
+Suppose we’ve got some values that implement `Foo`. The explicit form of
 construction and use of `Foo` trait objects might look a bit like (ignoring the
 type mismatches: they’re all just pointers anyway):
 

src/doc/trpl/traits.md

@@ -45,7 +45,7 @@ but we don’t define a body, just a type signature. When we `impl` a trait,
 we use `impl Trait for Item`, rather than just `impl Item`.
 
 We can use traits to constrain our generics. Consider this function, which
-does not compile, and gives us a similar error:
+does not compile:
 
 ```rust,ignore
 fn print_area<T>(shape: T) {
@@ -56,7 +56,7 @@ fn print_area<T>(shape: T) {
 Rust complains:
 
 ```text
-error: type `T` does not implement any method in scope named `area`
+error: no method named `area` found for type `T` in the current scope
 ```
 
 Because `T` can be any type, we can’t be sure that it implements the `area`
@@ -212,10 +212,10 @@ This will compile without error.
 This means that even if someone does something bad like add methods to `i32`,
 it won’t affect you, unless you `use` that trait.
 
-There’s one more restriction on implementing traits. Either the trait or the
-type you’re writing the `impl` for must be defined by you. So, we could
+There’s one more restriction on implementing traits: either the trait, or the
+type you’re writing the `impl` for, must be defined by you. So, we could
 implement the `HasArea` type for `i32`, because `HasArea` is in our code. But
-if we tried to implement `Float`, a trait provided by Rust, for `i32`, we could
+if we tried to implement `ToString`, a trait provided by Rust, for `i32`, we could
 not, because neither the trait nor the type are in our code.
 
 One last thing about traits: generic functions with a trait bound use