Merge remote-tracking branch 'origin/pr/2495'

src/ch04-01-what-is-ownership.md

@@ -216,7 +216,7 @@ from Listing 4-1 using a `String` instead of a string literal:
 
 There is a natural point at which we can return the memory our `String` needs
 to the allocator: when `s` goes out of scope. When a variable goes out
-of scope, Rust calls a special function for us. This function is called `drop`,
+of scope, Rust calls a special function for us. This function is called [`drop`](https://doc.rust-lang.org/std/ops/trait.Drop.html#tymethod.drop),
 and it’s where the author of `String` can put the code to return the memory.
 Rust calls `drop` automatically at the closing curly bracket.