Annotate root crate tests with standalone_crate

The new Rustdoc combined tests are an order of
magnitude slower in my machine for the `iced` root
crate.

src/application.rs

@@ -1,7 +1,7 @@
 //! Create and run iced applications step by step.
 //!
 //! # Example
-//! ```no_run
+//! ```no_run,standalone_crate
 //! use iced::widget::{button, column, text, Column};
 //! use iced::Theme;
 //!
@@ -42,7 +42,7 @@ use std::borrow::Cow;
 /// Creates an iced [`Application`] given its title, update, and view logic.
 ///
 /// # Example
-/// ```no_run
+/// ```no_run,standalone_crate
 /// use iced::widget::{button, column, text, Column};
 ///
 /// pub fn main() -> iced::Result {

src/lib.rs

@@ -29,7 +29,7 @@
 //! # The Pocket Guide
 //! Start by calling [`run`]:
 //!
-//! ```rust,no_run
+//! ```no_run,standalone_crate
 //! pub fn main() -> iced::Result {
 //!     iced::run("A cool counter", update, view)
 //! }
@@ -39,7 +39,7 @@
 //!
 //! Define an `update` function to __change__ your state:
 //!
-//! ```rust
+//! ```standalone_crate
 //! fn update(counter: &mut u64, message: Message) {
 //!     match message {
 //!         Message::Increment => *counter += 1,
@@ -51,7 +51,7 @@
 //!
 //! Define a `view` function to __display__ your state:
 //!
-//! ```rust
+//! ```standalone_crate
 //! use iced::widget::{button, text};
 //! use iced::Element;
 //!
@@ -64,7 +64,7 @@
 //!
 //! And create a `Message` enum to __connect__ `view` and `update` together:
 //!
-//! ```rust
+//! ```standalone_crate
 //! #[derive(Debug, Clone)]
 //! enum Message {
 //!     Increment,
@@ -74,7 +74,7 @@
 //! ## Custom State
 //! You can define your own struct for your state:
 //!
-//! ```rust
+//! ```standalone_crate
 //! #[derive(Default)]
 //! struct Counter {
 //!     value: u64,
@@ -83,7 +83,7 @@
 //!
 //! But you have to change `update` and `view` accordingly:
 //!
-//! ```rust
+//! ```standalone_crate
 //! # struct Counter { value: u64 }
 //! # #[derive(Clone)]
 //! # enum Message { Increment }
@@ -108,7 +108,7 @@
 //!
 //! Widgets are configured using the builder pattern:
 //!
-//! ```rust
+//! ```standalone_crate
 //! # struct Counter { value: u64 }
 //! # #[derive(Clone)]
 //! # enum Message { Increment }
@@ -138,7 +138,7 @@
 //! Building your layout will often consist in using a combination of
 //! [rows], [columns], and [containers]:
 //!
-//! ```rust
+//! ```standalone_crate
 //! # struct State;
 //! # enum Message {}
 //! use iced::widget::{column, container, row};
@@ -181,7 +181,7 @@
 //!
 //! A fixed numeric [`Length`] in [`Pixels`] can also be used:
 //!
-//! ```rust
+//! ```standalone_crate
 //! # struct State;
 //! # enum Message {}
 //! use iced::widget::container;
@@ -197,7 +197,7 @@
 //! function and leveraging the [`Application`] builder, instead of directly
 //! calling [`run`]:
 //!
-//! ```rust,no_run
+//! ```no_run,standalone_crate
 //! # #[derive(Default)]
 //! # struct State;
 //! use iced::Theme;
@@ -227,7 +227,7 @@
 //!
 //! The appearance of a widget can be changed by calling its `style` method:
 //!
-//! ```rust
+//! ```standalone_crate
 //! # struct State;
 //! # enum Message {}
 //! use iced::widget::container;
@@ -241,7 +241,7 @@
 //! The `style` method of a widget takes a closure that, given the current active
 //! [`Theme`], returns the widget style:
 //!
-//! ```rust
+//! ```standalone_crate
 //! # struct State;
 //! # #[derive(Clone)]
 //! # enum Message {}
@@ -286,7 +286,7 @@
 //! A [`Task`] can be leveraged to perform asynchronous work, like running a
 //! future or a stream:
 //!
-//! ```rust
+//! ```standalone_crate
 //! # #[derive(Clone)]
 //! # struct Weather;
 //! use iced::Task;
@@ -334,7 +334,7 @@
 //!
 //! You will need to define a `subscription` function and use the [`Application`] builder:
 //!
-//! ```rust,no_run
+//! ```no_run,standalone_crate
 //! # #[derive(Default)]
 //! # struct State;
 //! use iced::window;
@@ -375,7 +375,7 @@
 //! A common pattern is to leverage this composability to split an
 //! application into different screens:
 //!
-//! ```rust
+//! ```standalone_crate
 //! # mod contacts {
 //! #     use iced::{Element, Task};
 //! #     pub struct Contacts;
@@ -656,7 +656,7 @@ pub type Result = std::result::Result<(), Error>;
 /// This is equivalent to chaining [`application()`] with [`Application::run`].
 ///
 /// # Example
-/// ```no_run
+/// ```no_run,standalone_crate
 /// use iced::widget::{button, column, text, Column};
 ///
 /// pub fn main() -> iced::Result {