Rollup merge of #82063 - NULLx76:fix-minor-typo, r=jonas-schievink

Fixed minor typo in catch_unwind docs

Changed "a an exception" to "an exception" inside of the `std::panic::catch_unwind` docs.

library/std/src/panic.rs

@@ -408,7 +408,7 @@ impl<S: Stream> Stream for AssertUnwindSafe<S> {
 /// aborting the process as well. This function *only* catches unwinding panics,
 /// not those that abort the process.
 ///
-/// Also note that unwinding into Rust code with a foreign exception (e.g. a
+/// Also note that unwinding into Rust code with a foreign exception (e.g.
 /// an exception thrown from C++ code) is undefined behavior.
 ///
 /// # Examples