setup: Set readme content-type explicitly

Silences a warning when uploading to pypi.

diff --git a/setup.py b/setup.py
index bb4f82305fd166d53f03b1e9c51d25dc0b2f1d93..404090fcfa6e1f29a1ef9cb63afe60be4cf0ecec 100644 (file)
--- a/setup.py
+++ b/setup.py
@@ -120,6 +120,7 @@ with open("tornado/__init__.py") as f:
 
 with open("README.rst") as f:
     kwargs["long_description"] = f.read()
+    kwargs["long_description_content_type"] = "text/x-rst"
 
 if (
     platform.python_implementation() == "CPython"