Fix doc tests to work whether or not serde derive feature is used

serde/src/de/mod.rs

@@ -2240,8 +2240,8 @@ pub trait VariantAccess<'de>: Sized {
 ///
 /// ```edition2021
 /// use std::str::FromStr;
-/// use serde::Deserialize;
-/// use serde::de::{value, IntoDeserializer};
+/// use serde::de::{value, Deserialize, IntoDeserializer};
+/// use serde_derive::Deserialize;
 ///
 /// #[derive(Deserialize)]
 /// enum Setting {

serde/src/de/value.rs

@@ -3,8 +3,8 @@
 //!
 //! ```edition2021
 //! use std::str::FromStr;
-//! use serde::Deserialize;
-//! use serde::de::{value, IntoDeserializer};
+//! use serde_derive::Deserialize;
+//! use serde::de::{value, Deserialize, IntoDeserializer};
 //!
 //! #[derive(Deserialize)]
 //! enum Setting {

serde/src/ser/fmt.rs

@@ -18,7 +18,8 @@ macro_rules! fmt_primitives {
 }
 
 /// ```edition2021
-/// use serde::Serialize;
+/// use serde::ser::Serialize;
+/// use serde_derive::Serialize;
 /// use std::fmt::{self, Display};
 ///
 /// #[derive(Serialize)]