Merge pull request #825 from slivingston/update-docs

docs(readme): Update example to prefer DocumentMut

Author: epage

crates/toml_edit/README.md

@@ -16,14 +16,14 @@ relative order* of items.
 ## Example
 
 ```rust
-use toml_edit::{Document, value};
+use toml_edit::{DocumentMut, value};
 
 fn main() {
     let toml = r#"
 "hello" = 'toml!' # comment
 ['a'.b]
     "#;
-    let mut doc = toml.parse::<Document>().expect("invalid doc");
+    let mut doc = toml.parse::<DocumentMut>().expect("invalid doc");
     assert_eq!(doc.to_string(), toml);
     // let's add a new key/value pair inside a.b: c = {d = "hello"}
     doc["a"]["b"]["c"]["d"] = value("hello");