Revert "Add known issue of let binding to format_args doc"

This reverts commit cd7c161.

Author: tshepang

library/core/src/macros/mod.rs

@@ -975,14 +975,6 @@ pub(crate) mod builtin {
     /// let s = fmt::format(format_args!("hello {}", "world"));
     /// assert_eq!(s, format!("hello {}", "world"));
     /// ```
-    ///
-    /// # Lifetime limitation
-    ///
-    /// Except when no formatting arguments are used,
-    /// the produced `fmt::Arguments` value borrows temporary values,
-    /// which means it can only be used within the same expression
-    /// and cannot be stored for later use.
-    /// This is a known limitation, see [#92698](https://github.com/rust-lang/rust/issues/92698).
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_diagnostic_item = "format_args_macro"]
     #[allow_internal_unsafe]