Fix Windows mime types bug

Author: Archmonger

src/py/reactpy/reactpy/backend/__init__.py

@@ -0,0 +1,7 @@
+import mimetypes
+
+# Fix for issue where Windows registry gets corrupt and mime types go missing
+mimetypes.init()
+for extension, type in mimetypes.common_types.items():
+    if not mimetypes.types_map.get(extension):
+        mimetypes.add_type(type, extension)