python/nest_asyncio: Wrap README at 72 columns.

Signed-off-by: B. Watson <yalhcru@gmail.com>

python/nest_asyncio/README

@@ -1,7 +1,8 @@
-By design asyncio does not allow its event loop to be nested. This presents a
-practical problem: When in an environment where the event loop is already
-running it's impossible to run tasks and wait for the result. Trying to do so
-will give the error "RuntimeError: This event loop is already running".
+By design asyncio does not allow its event loop to be nested. This
+presents a practical problem: When in an environment where the event
+loop is already running it's impossible to run tasks and wait for the
+result. Trying to do so will give the error "RuntimeError: This event
+loop is already running".
 
 The issue pops up in various environments, such as web servers, GUI
 applications and in Jupyter notebooks.