rollup merge of #20632: gchp/reference

I noticed that the `deriving` keyword is deprecated and that `derive` is the replacement. This updates the reference (and other docs) to remove the use `deriving`.

src/doc/reference.md

@@ -2432,15 +2432,15 @@ There are three different types of inline attributes:
 * `#[inline(always)]` asks the compiler to always perform an inline expansion.
 * `#[inline(never)]` asks the compiler to never perform an inline expansion.
 
-### Deriving
+### Derive
 
-The `deriving` attribute allows certain traits to be automatically implemented
+The `derive` attribute allows certain traits to be automatically implemented
 for data structures. For example, the following will create an `impl` for the
 `PartialEq` and `Clone` traits for `Foo`, the type parameter `T` will be given
 the `PartialEq` or `Clone` constraints for the appropriate `impl`:
 
 ```
-#[deriving(PartialEq, Clone)]
+#[derive(PartialEq, Clone)]
 struct Foo<T> {
     a: int,
     b: T
@@ -2462,7 +2462,7 @@ impl<T: PartialEq> PartialEq for Foo<T> {
 }
 ```
 
-Supported traits for `deriving` are:
+Supported traits for `derive` are:
 
 * Comparison traits: `PartialEq`, `Eq`, `PartialOrd`, `Ord`.
 * Serialization: `Encodable`, `Decodable`. These require `serialize`.

src/doc/rustdoc.md

@@ -198,7 +198,7 @@ Rustdoc also supplies some extra sugar for helping with some tedious
 documentation examples. If a line is prefixed with `# `, then the line
 will not show up in the HTML documentation, but it will be used when
 testing the code block (NB. the space after the `#` is required, so
-that one can still write things like `#[deriving(Eq)]`).
+that one can still write things like `#[derive(Eq)]`).
 
 ~~~md
 ```

src/doc/trpl/plugins.md

@@ -126,7 +126,7 @@ The advantages over a simple `fn(&str) -> uint` are:
   a way to define new literal syntax for any data type.
 
 In addition to procedural macros, you can define new
-[`deriving`](../reference.html#deriving)-like attributes and other kinds of
+[`derive`](../reference.html#derive)-like attributes and other kinds of
 extensions.  See
 [`Registry::register_syntax_extension`](../rustc/plugin/registry/struct.Registry.html#method.register_syntax_extension)
 and the [`SyntaxExtension`