doctoc update

Author: ghik

docs/GenCodec.md

@@ -9,30 +9,32 @@ serialization libraries like [Circe](https://circe.github.io/circe/) or [uPickle
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 ## Table of Contents  *generated with [DocToc](https://github.com/thlorenz/doctoc)*
 
-- [`GenCodec`](#gencodec)
-  - [`GenCodec` typeclass](#gencodec-typeclass)
-  - [Codecs available by default](#codecs-available-by-default)
-  - [`GenKeyCodec`](#genkeycodec)
-  - [Serializing and deserializing examples](#serializing-and-deserializing-examples)
-  - [Making your own types serializable](#making-your-own-types-serializable)
-  - [Simple types](#simple-types)
-  - [Case classes](#case-classes)
-      - [Safe evolution and refactoring - summary](#safe-evolution-and-refactoring---summary)
-    - [Case class like types](#case-class-like-types)
-  - [Singletons](#singletons)
-  - [Sealed hierarchies](#sealed-hierarchies)
-    - [Nested format](#nested-format)
-    - [Flat format](#flat-format)
-    - [Customizing sealed hierarchy codecs](#customizing-sealed-hierarchy-codecs)
-    - [Nested vs flat format](#nested-vs-flat-format)
-  - [Third party classes](#third-party-classes)
-  - [Summary](#summary)
-    - [Codec dependencies](#codec-dependencies)
-    - [Types supported by automatic materialization](#types-supported-by-automatic-materialization)
-    - [Recursive types, generic types and GADTs (generalized algebraic data types)](#recursive-types-generic-types-and-gadts-generalized-algebraic-data-types)
-    - [Customizing annotations](#customizing-annotations)
-    - [Safely introducing changes to serialized classes (retaining backwards compatibility)](#safely-introducing-changes-to-serialized-classes-retaining-backwards-compatibility)
-  - [Performance](#performance)
+- [`GenCodec` typeclass](#gencodec-typeclass)
+  - [Writing *lists* and *objects*](#writing-lists-and-objects)
+    - [Object field order](#object-field-order)
+  - [Implementations of `Input` and `Output` available by default](#implementations-of-input-and-output-available-by-default)
+- [Codecs available by default](#codecs-available-by-default)
+- [`GenKeyCodec`](#genkeycodec)
+- [Serializing and deserializing examples](#serializing-and-deserializing-examples)
+- [Making your own types serializable](#making-your-own-types-serializable)
+- [Simple types](#simple-types)
+- [Case classes](#case-classes)
+    - [Safe evolution and refactoring - summary](#safe-evolution-and-refactoring---summary)
+  - [Case class like types](#case-class-like-types)
+- [Singletons](#singletons)
+- [Sealed hierarchies](#sealed-hierarchies)
+  - [Nested format](#nested-format)
+  - [Flat format](#flat-format)
+  - [Customizing sealed hierarchy codecs](#customizing-sealed-hierarchy-codecs)
+  - [Nested vs flat format](#nested-vs-flat-format)
+- [Third party classes](#third-party-classes)
+- [Summary](#summary)
+  - [Codec dependencies](#codec-dependencies)
+  - [Types supported by automatic materialization](#types-supported-by-automatic-materialization)
+  - [Recursive types, generic types and GADTs (generalized algebraic data types)](#recursive-types-generic-types-and-gadts-generalized-algebraic-data-types)
+  - [Customizing annotations](#customizing-annotations)
+  - [Safely introducing changes to serialized classes (retaining backwards compatibility)](#safely-introducing-changes-to-serialized-classes-retaining-backwards-compatibility)
+- [Performance](#performance)
 
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