Use serde's `derive` feature instead of directly importing serde_derive

Cargo.lock

@@ -865,7 +865,6 @@ dependencies = [
  "select",
  "semver",
  "serde",
- "serde_derive",
  "serde_json",
  "shlex",
  "tempfile",
@@ -1483,6 +1482,9 @@ name = "serde"
 version = "1.0.129"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d1f72836d2aa753853178eda473a3b9d8e4eefdaf20523b919677e6de489f8f1"
+dependencies = [
+ "serde_derive",
+]
 
 [[package]]
 name = "serde_derive"

Cargo.toml

@@ -28,8 +28,7 @@ memchr = "2.0"
 opener = "0.5"
 pulldown-cmark = { version = "0.9.1", default-features = false }
 regex = "1.5.5"
-serde = "1.0"
-serde_derive = "1.0"
+serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 shlex = "1"
 tempfile = "3.0"

src/book/book.rs

@@ -9,6 +9,8 @@ use crate::config::BuildConfig;
 use crate::errors::*;
 use crate::utils::bracket_escape;
 
+use serde::{Deserialize, Serialize};
+
 /// Load a book into memory from its `src/` directory.
 pub fn load_book<P: AsRef<Path>>(src_dir: P, cfg: &BuildConfig) -> Result<Book> {
     let src_dir = src_dir.as_ref();

src/book/summary.rs

@@ -1,6 +1,7 @@
 use crate::errors::*;
 use memchr::{self, Memchr};
 use pulldown_cmark::{self, Event, HeadingLevel, Tag};
+use serde::{Deserialize, Serialize};
 use std::fmt::{self, Display, Formatter};
 use std::iter::FromIterator;
 use std::ops::{Deref, DerefMut};

src/lib.rs

@@ -89,8 +89,6 @@ extern crate lazy_static;
 #[macro_use]
 extern crate log;
 #[macro_use]
-extern crate serde_derive;
-#[macro_use]
 extern crate serde_json;
 
 #[cfg(test)]

src/preprocess/mod.rs

@@ -16,6 +16,8 @@ use std::cell::RefCell;
 use std::collections::HashMap;
 use std::path::PathBuf;
 
+use serde::{Deserialize, Serialize};
+
 /// Extra information for a `Preprocessor` to give them more context when
 /// processing a book.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]

src/renderer/html_handlebars/search.rs

@@ -11,6 +11,8 @@ use crate::errors::*;
 use crate::theme::searcher;
 use crate::utils;
 
+use serde::Serialize;
+
 /// Creates all files required for search.
 pub fn create_files(search_config: &Search, destination: &Path, book: &Book) -> Result<()> {
     let mut index = Index::new(&["title", "body", "breadcrumbs"]);

src/renderer/mod.rs

@@ -29,6 +29,8 @@ use crate::config::Config;
 use crate::errors::*;
 use toml::Value;
 
+use serde::{Deserialize, Serialize};
+
 /// An arbitrary `mdbook` backend.
 ///
 /// Although it's quite possible for you to import `mdbook` as a library and