doc: uv_read_stop always succeeds

Fixes: https://github.com/libuv/libuv/issues/3041
PR-URL: https://github.com/libuv/libuv/pull/3076
Reviewed-By: Jameson Nash <vtjnash@gmail.com>

docs/src/stream.rst

@@ -145,6 +145,11 @@ API
     no longer be called.
 
     This function is idempotent and may be safely called on a stopped stream.
+    
+    This function will always succeed; hence, checking its return value is
+    unnecessary. A non-zero return indicates that finishing releasing resources
+    may be pending on the next input event on that TTY on Windows, and does not 
+    indicate failure.
 
 .. c:function:: int uv_write(uv_write_t* req, uv_stream_t* handle, const uv_buf_t bufs[], unsigned int nbufs, uv_write_cb cb)