Itertools::format[_with] docs mention it can panic if used in logging macros

Author: Philippe-Cholet

src/lib.rs

@@ -2319,6 +2319,8 @@ pub trait Itertools: Iterator {
     /// with `sep` inserted between each element.
     ///
     /// **Panics** if the formatter helper is formatted more than once.
+    /// ⚠ This can happen unexpectedly and be hard to debug if used in
+    /// _macros of some logging frameworks_ like `tracing`! ⚠
     ///
     /// ```
     /// use itertools::Itertools;
@@ -2339,15 +2341,17 @@ pub trait Itertools: Iterator {
     ///
     /// This is a customizable version of [`.format()`](Itertools::format).
     ///
+    /// **Panics** if the formatter helper is formatted more than once.
+    /// ⚠ This can happen unexpectedly and be hard to debug if used in
+    /// _macros of some logging frameworks_ like `tracing`! ⚠
+    ///
     /// The supplied closure `format` is called once per iterator element,
     /// with two arguments: the element and a callback that takes a
     /// `&Display` value, i.e. any reference to type that implements `Display`.
     ///
     /// Using `&format_args!(...)` is the most versatile way to apply custom
     /// element formatting. The callback can be called multiple times if needed.
     ///
-    /// **Panics** if the formatter helper is formatted more than once.
-    ///
     /// ```
     /// use itertools::Itertools;
     ///