add IDEA support for CBC, CFB, OFB + tests for all IDEA
diff --git a/docs/hazmat/primitives/symmetric-encryption.rst b/docs/hazmat/primitives/symmetric-encryption.rst
index daa4b36..741091b 100644
--- a/docs/hazmat/primitives/symmetric-encryption.rst
+++ b/docs/hazmat/primitives/symmetric-encryption.rst
@@ -172,8 +172,8 @@
     is susceptible to attacks when using weak keys. It is recommended that you
     do not use this cipher for new applications.
 
-    :param bytes key: The secret key, 128 bits in length.  This must be kept
-                      secret.
+    :param bytes key: The secret key This must be kept secret. ``128`` bits in
+        length.
 
 
 .. _symmetric-encryption-modes: