Auto merge of #13193 - alex-semenyuk:fix_doc_unused_io_amount, r=xFrednet

Fix doc example for UNUSED_IO_AMOUNT

Cosmetic changes. Unify example for UNUSED_IO_AMOUNT

changelog: none

Author: bors

clippy_lints/src/unused_io_amount.rs

@@ -34,11 +34,18 @@ declare_clippy_lint! {
     /// ```rust,ignore
     /// use std::io;
     /// fn foo<W: io::Write>(w: &mut W) -> io::Result<()> {
-    ///     // must be `w.write_all(b"foo")?;`
     ///     w.write(b"foo")?;
     ///     Ok(())
     /// }
     /// ```
+    /// Use instead:
+    /// ```rust,ignore
+    /// use std::io;
+    /// fn foo<W: io::Write>(w: &mut W) -> io::Result<()> {
+    ///     w.write_all(b"foo")?;
+    ///     Ok(())
+    /// }
+    /// ```
     #[clippy::version = "pre 1.29.0"]
     pub UNUSED_IO_AMOUNT,
     correctness,