docs: add logging classes to references

docs/references.rst

@@ -13,4 +13,11 @@ Format Classes
 
 .. autoclass:: redmail.models.EmailAddress
 
-.. autoclass:: redmail.models.Error
+.. autoclass:: redmail.models.Error
+
+Logging Classes
+---------------
+
+.. autoclass:: redmail.EmailHandler
+
+.. autoclass:: redmail.MultiEmailHandler