Interfaces for SCTs, feedback wanted (#3467)

* Stub API for SCTs, feedback wanted

* grr, flake8

* port this to being an ABC

* finish up the __init__

* Two necessary enums

* Roll this back

* Wrote some docs

* spell words correctly

* linky

* more details

* use the words UTC

* coverage

* Define MMD for the kids at some

* linky linky
diff --git a/docs/x509/index.rst b/docs/x509/index.rst
index 2e3aa74..ec47fe6 100644
--- a/docs/x509/index.rst
+++ b/docs/x509/index.rst
@@ -9,6 +9,7 @@
     :maxdepth: 2
 
     tutorial
+    certificate-transparency
     reference
 
 .. _`public key infrastructure`: https://en.wikipedia.org/wiki/Public_key_infrastructure