Fixed mismatched parameter documentation
diff --git a/OpenSSL/crypto.py b/OpenSSL/crypto.py
index 7b2ce07..132d98d 100644
--- a/OpenSSL/crypto.py
+++ b/OpenSSL/crypto.py
@@ -627,9 +627,9 @@
"""
Initializes an X509 extension.
- :param typename: The name of the type of extension to create. See
+ :param type_name: The name of the type of extension to create. See
http://openssl.org/docs/apps/x509v3_config.html#STANDARD_EXTENSIONS
- :type typename: :py:data:`bytes`
+ :type type_name: :py:data:`bytes`
:param bool critical: A flag indicating whether this is a critical
extension.