Rollup merge of rust-lang#45113 - Pirh:process_output_links, r=steveklabnik

Link std::process::Output to Command and Child

As per rust-lang#29370

Author: kennytm

src/libstd/process.rs

@@ -702,6 +702,15 @@ impl AsInnerMut<imp::Command> for Command {
 }
 
 /// The output of a finished process.
+///
+/// This is returned in a Result by either the [`output`] method of a
+/// [`Command`], or the [`wait_with_output`] method of a [`Child`]
+/// process.
+///
+/// [`Command`]: struct.Command.html
+/// [`Child`]: struct.Child.html
+/// [`output`]: struct.Command.html#method.output
+/// [`wait_with_output`]: struct.Child.html#method.wait_with_output
 #[derive(PartialEq, Eq, Clone)]
 #[stable(feature = "process", since = "1.0.0")]
 pub struct Output {