Fix markup to be compatible with Sphinx and add rough API doc
diff --git a/OpenSSL/crypto/x509ext.c b/OpenSSL/crypto/x509ext.c
index 96c1993..f65fd0f 100644
--- a/OpenSSL/crypto/x509ext.c
+++ b/OpenSSL/crypto/x509ext.c
@@ -54,7 +54,7 @@
static char crypto_X509Extension_get_data_doc[] = "\n\
Returns the data of the X509Extension\n\
\n\
-:return: A C{str} giving the X509Extension's ASN.1 encoded data.\n\
+:return: A :py:data:`str` giving the X509Extension's ASN.1 encoded data.\n\
";
static PyObject *
@@ -186,14 +186,14 @@
X509Extension instance\n\
\n\
:param typename: The name of the extension to create.\n\
-:type typename: C{str}\n\
+:type typename: :py:data:`str`\n\
:param critical: A flag indicating whether this is a critical extension.\n\
:param value: The value of the extension.\n\
-:type value: C{str}\n\
+:type value: :py:data:`str`\n\
:param subject: Optional X509 cert to use as subject.\n\
-:type subject: C{X509}\n\
+:type subject: :py:class:`X509`\n\
:param issuer: Optional X509 cert to use as issuer.\n\
-:type issuer: C{X509}\n\
+:type issuer: :py:class:`X509`\n\
:return: The X509Extension object\n\
";