Auto merge of #6023 - matthiaskrgr:box, r=flip1995

link to the Box docs in related lint documentation.

changelog: link to the box docs in lint docs

clippy_lints/src/types.rs

@@ -37,6 +37,7 @@
 
 declare_clippy_lint! {
     /// **What it does:** Checks for use of `Box<Vec<_>>` anywhere in the code.
+    /// Check the [Box documentation](https://doc.rust-lang.org/std/boxed/index.html) for more information.
     ///
     /// **Why is this bad?** `Vec` already keeps its contents in a separate area on
     /// the heap. So if you `Box` it, you just add another level of indirection
@@ -65,6 +66,7 @@
 
 declare_clippy_lint! {
     /// **What it does:** Checks for use of `Vec<Box<T>>` where T: Sized anywhere in the code.
+    /// Check the [Box documentation](https://doc.rust-lang.org/std/boxed/index.html) for more information.
     ///
     /// **Why is this bad?** `Vec` already keeps its contents in a separate area on
     /// the heap. So if you `Box` its contents, you just add another level of indirection.
@@ -167,6 +169,7 @@
 
 declare_clippy_lint! {
     /// **What it does:** Checks for use of `&Box<T>` anywhere in the code.
+    /// Check the [Box documentation](https://doc.rust-lang.org/std/boxed/index.html) for more information.
     ///
     /// **Why is this bad?** Any `&Box<T>` can also be a `&T`, which is more
     /// general.