Update src/iter/mod.rs
//! `None`/`Err` values will exit early.
//!
//! A note about object safety: It is currently _not_ possible to wrap
-//! a ParallelIterator (or any trait that depends on it) using a
+//! a `ParallelIterator` (or any trait that depends on it) using a
//! `Box<dyn ParallelIterator>` or other kind of dynamic allocation,
//! because `ParallelIterator` is **not object-safe**.
//! (This keeps the implementation simpler and allows extra optimizations.)
