Document typing.NoReturn (GH-7107)

(cherry picked from commit 6e413f4327a68c4c7d62e0b6d0f9144be11dd6cd)

Co-authored-by: Ivan Levkivskyi <levkivskyi@gmail.com>
diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst
index be6636e..91d10e3 100644
--- a/Doc/library/typing.rst
+++ b/Doc/library/typing.rst
@@ -937,6 +937,18 @@
    * Every type is compatible with :data:`Any`.
    * :data:`Any` is compatible with every type.
 
+.. data:: NoReturn
+
+   Special type indicating that a function never returns.
+   For example::
+
+      from typing import NoReturn
+
+      def stop() -> NoReturn:
+          raise RuntimeError('no way')
+
+   .. versionadded:: 3.6.5
+
 .. data:: Union
 
    Union type; ``Union[X, Y]`` means either X or Y.