Rollup merge of rust-lang#25530 - peferron:doc-closures-whitespace-fix, r=alexcrichton

Tiny fixes collected while reading through the Rust book. If they're too nitpicky please let me know and I'll ignore the next ones. :)

The spaces after the function and closure arguments might be intentional, but they do not make much sense: the usual formatting doesn't have such spaces, and they aren't helping align the three lines together either.

r? @steveklabnik (as suggested by [CONTRIBUTING.md](https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md))

Author: Manishearth

src/doc/trpl/closures.md

@@ -54,9 +54,9 @@ The second is that the syntax is similar, but a bit different. I’ve added spac
 here to make them look a little closer:
 
 ```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  ;
+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.
@@ -136,7 +136,7 @@ This gives us:
 note: `nums` moved into closure environment here because it has type
   `[closure(()) -> collections::vec::Vec<i32>]`, which is non-copyable
 let takes_nums = || nums;
-                    ^~~~~~~
+                 ^~~~~~~
 ```
 
 `Vec<T>` has ownership over its contents, and therefore, when we refer to it
@@ -352,8 +352,8 @@ error: the trait `core::marker::Sized` is not implemented for the type
 factory() -> (Fn(i32) -> Vec<i32>) {
              ^~~~~~~~~~~~~~~~~~~~~
 note: `core::ops::Fn(i32) -> collections::vec::Vec<i32>` does not have a constant size known at compile-time
-fa ctory() -> (Fn(i32) -> Vec<i32>) {
-              ^~~~~~~~~~~~~~~~~~~~~
+factory() -> (Fn(i32) -> Vec<i32>) {
+             ^~~~~~~~~~~~~~~~~~~~~
 
 ```