Add doctests for the traits.

Author: artob

README.md

@@ -59,10 +59,10 @@ struct Rectangle {
     height: u32,
 }
 
-impl Tldr for Rectangle {
+impl Tldr<String> for Rectangle {
     type Error = Box<dyn Error>;
 
-    fn what(&self, _ctx: &TldrContext) -> TldrResult<T> {
+    fn what(&self, _ctx: &TldrContext) -> TldrResult<String> {
         Ok(Some(format!("A rectangle with a width of {} and a height of {}.", self.width, self.height)))
     }
 }

src/language.rs

@@ -5,6 +5,7 @@ use core::{fmt, str::FromStr};
 
 /// ```rust
 /// # use tldr_traits::TldrLanguage;
+/// let language = TldrLanguage::default(); // this is the same as...
 /// let language = TldrLanguage::English;
 /// ```
 #[non_exhaustive]

src/traits/tldr.rs

@@ -3,6 +3,23 @@
 use crate::{TldrContext, TldrResult};
 use alloc::string::String;
 
+/// ```rust
+/// # use tldr_traits::{Tldr, TldrContext, TldrResult};
+/// # use core::error::Error;
+/// struct Rectangle {
+///     width: u32,
+///     height: u32,
+/// }
+///
+/// impl Tldr<String> for Rectangle {
+///     type Error = Box<dyn Error>;
+///
+///     fn what(&self, _ctx: &TldrContext) -> TldrResult<String> {
+///         Ok(Some(format!("A rectangle with a width of {} and a height of {}.", self.width, self.height)))
+///     }
+/// }
+/// ```
+///
 /// See: https://en.wikipedia.org/wiki/Five_Ws
 /// See: https://en.wikipedia.org/wiki/Interrogative_word
 pub trait Tldr<T = String> {

src/traits/to_tldr.rs

@@ -3,6 +3,21 @@
 use crate::Tldr;
 use alloc::{boxed::Box, string::String};
 
+/// ```rust
+/// # use tldr_traits::{Tldr, TldrSummary, ToTldr};
+/// struct Rectangle {
+///     width: u32,
+///     height: u32,
+/// }
+///
+/// impl ToTldr<String> for Rectangle {
+///     type Error = Box<dyn core::error::Error>;
+///
+///     fn to_tldr(&self) -> Box<dyn Tldr<String, Error = Self::Error>> {
+///         todo!() // FIXME
+///     }
+/// }
+/// ```
 pub trait ToTldr<T = String> {
     /// The associated error type.
     ///