Add missing @noreturn to os::exit

lib/std/os/os.c3

@@ -4,7 +4,7 @@ import libc;
 <*
  Exit the process with a given exit code. This will typically call 'exit' in LibC
 *>
-fn void exit(int result, bool cleanup = true) @weak
+fn void exit(int result, bool cleanup = true) @weak @noreturn
 {
 	$if env::LIBC:
 		libc::exit(result);
@@ -17,7 +17,7 @@ fn void exit(int result, bool cleanup = true) @weak
  Exit the process with a given exit code. This will typically call '_Exit' in LibC
  usually bypassing '@finalizer' functions.
 *>
-fn void fastexit(int result, bool cleanup = true) @weak
+fn void fastexit(int result, bool cleanup = true) @weak @noreturn
 {
 	$if env::LIBC:
 		libc::_exit(result);

releasenotes.md

@@ -39,6 +39,7 @@
 - `&&&` was accidentally available as a valid prefix operator.
 - Missing error on default values for body with default arguments #2148.
 - `--path` does not interact correctly with relative path arguments #2149.
+- Add missing `@noreturn` to `os::exit`.
 
 ### Stdlib changes
 - Added `String.quick_ztr` and `String.is_zstr`