Fix "unresolved link to std::fmt::Error"

error: unresolved link to `std::fmt::Error`
       --> library/core/src/fmt/mod.rs:115:52
        |
    115 |     /// This function will return an instance of [`std::fmt::Error`] on error.
        |
        |
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

Author: dtolnay

library/core/src/fmt/mod.rs

@@ -112,7 +112,7 @@ pub trait Write {
     ///
     /// # Errors
     ///
-    /// This function will return an instance of [`std::fmt::Error`] on error.
+    /// This function will return an instance of [`std::fmt::Error`][Error] on error.
     ///
     /// The purpose of that error is to abort the formatting operation when the underlying
     /// destination encounters some error preventing it from accepting more text; it should