Merge pull request #1042 from alex/improve-docs

Fixed #1039 -- provide links to PSS and PKCS1v15 in the RSA docs
diff --git a/docs/hazmat/primitives/asymmetric/rsa.rst b/docs/hazmat/primitives/asymmetric/rsa.rst
index 7bae714..234a5c6 100644
--- a/docs/hazmat/primitives/asymmetric/rsa.rst
+++ b/docs/hazmat/primitives/asymmetric/rsa.rst
@@ -85,7 +85,10 @@
 
         :param padding: An instance of a
             :class:`~cryptography.hazmat.primitives.interfaces.AsymmetricPadding`
-            provider.
+            provider. Valid values are
+            :class:`~cryptography.hazmat.primitives.asymmetric.padding.PSS` and
+            :class:`~cryptography.hazmat.primitives.asymmetric.padding.PKCS1v15`
+            (``PSS`` is recommended for all new applications).
 
         :param algorithm: An instance of a
             :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
@@ -254,7 +257,10 @@
 
         :param padding: An instance of a
             :class:`~cryptography.hazmat.primitives.interfaces.AsymmetricPadding`
-            provider.
+            provider. Valid values are
+            :class:`~cryptography.hazmat.primitives.asymmetric.padding.PSS` and
+            :class:`~cryptography.hazmat.primitives.asymmetric.padding.PKCS1v15`
+            (``PSS`` is recommended for all new applications).
 
         :param algorithm: An instance of a
             :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`