docs: use backticks for all type links

Signed-off-by: Nathaniel McCallum <nathaniel@profian.com>

axum-core/src/response/mod.rs

@@ -20,15 +20,15 @@ pub use self::{
 /// type used with axum.
 pub type Response<T = BoxBody> = http::Response<T>;
 
-/// A flexible [IntoResponse]-based result type
+/// A flexible [`IntoResponse`]-based result type
 ///
-/// All types which implement [IntoResponse] can be converted to an [ErrorResponse].
+/// All types which implement [`IntoResponse`] can be converted to an [`ErrorResponse`].
 /// This makes it useful as a general error type for functions which combine
-/// multiple distinct error types but all of which implement [IntoResponse].
+/// multiple distinct error types but all of which implement [`IntoResponse`].
 ///
 /// For example, note that the error types below differ. However, both can be
-/// used with the [Result], and therefore the `?` operator, since they both
-/// implement [IntoResponse].
+/// used with the [`Result`], and therefore the `?` operator, since they both
+/// implement [`IntoResponse`].
 ///
 /// ```no_run
 /// use axum::{
@@ -64,9 +64,9 @@ where
     }
 }
 
-/// An [IntoResponse]-based error type
+/// An [`IntoResponse`]-based error type
 ///
-/// See [Result] for more details.
+/// See [`Result`] for more details.
 #[derive(Debug)]
 pub struct ErrorResponse(Response);