Add reference to sidebar

Author: odersky

docs/docs/reference/enums.md

@@ -1,6 +1,6 @@
-# Enums
+# Enumerations
 
-The most basic use of enums is as enumerations of simple values:
+An enumeration is used to define a type consisting of a set of named values.
 
 ```scala
 enum Color {

docs/sidebar.yml

@@ -3,6 +3,18 @@ sidebar:
       url: blog/index.html
     - title: Docs
       url: docs/index.html
+    - title: Reference
+      subsection:
+        - title: Trait Parameters
+          url: docs/reference/trait-parameters.html
+        - title: Enumerations
+          url: docs/reference/enums.html
+        - title: Algebraic Data Types
+          url: docs/reference/adts.html
+        - title: Enum Translation
+          url: docs/reference/desugarEnums.html
+        - title: By-Name Implicits
+          url: docs/reference/implicit-by-name-parameters.html
     - title: Usage
       subsection:
         - title: cbt-projects