update doc examples

- Make examples runnable for doc tests
- Add error handling using `?` instead of `unwrap`

src/response.rs

@@ -87,27 +87,31 @@ impl Response {
         }
     }
 
-    /// Try and deserialize the response body as JSON.
+    /// Try and deserialize the response body as JSON using `serde`.
     ///
     /// # Examples
     ///
-    /// ```rust,no_run
-    /// extern crate reqwest;
-    /// #[macro_use]
-    /// extern crate serde_derive;
-    ///
+    /// ```rust
+    /// # extern crate reqwest;
+    /// # #[macro_use] extern crate serde_derive;
+    /// #
+    /// # use reqwest::Error;
+    /// #
     /// #[derive(Deserialize)]
-    /// struct User {
-    ///     name: String,
-    ///     age: u8,
+    /// struct Response {
+    ///     origin: String,
     /// }
     ///
-    /// fn main() {
-    ///     let user: User = reqwest::get("http://127.0.0.1/user.json")
-    ///         .expect("network error")
-    ///         .json()
-    ///         .expect("malformed json");
-    /// }
+    /// # fn run() -> Result<(), Error> {
+    /// let resp: Response = reqwest::get("http://127.0.0.1/user.json")?.json()?;
+    /// # Ok(())
+    /// # }
+    /// #
+    /// # fn main() {
+    /// #     if let Err(error) = run() {
+    /// #         println!("Error: {:?}", error);
+    /// #     }
+    /// # }
     /// ```
     #[inline]
     pub fn json<T: DeserializeOwned>(&mut self) -> ::Result<T> {