Add an updated TOC (table of contents)

Uses markdown-toc:
markdown-toc --maxdepth 4 -i

Author: lornajane

versions/3.0.4.md

@@ -20,6 +20,86 @@ For extension registries and other specifications published by the OpenAPI Initi
 
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+* [Definitions](#definitions)
+  * [OpenAPI Description](#openapi-description)
+  * [Schema](#schema)
+  * [Path Templating](#path-templating)
+  * [Media Types](#media-types)
+  * [HTTP Status Codes](#http-status-codes)
+  * [HTTP and Case Sensitivity](#http-and-case-sensitivity)
+  * [Undefined and Implementation-Defined Behavior](#undefined-and-implementation-defined-behavior)
+* [Specification](#specification)
+  * [Versions](#versions)
+  * [Format](#format)
+  * [OpenAPI Description Structure](#openapi-description-structure)
+    * [Structural Interoperability](#structural-interoperability)
+    * [Resolving Implicit Connections](#resolving-implicit-connections)
+  * [Data Types](#data-types)
+    * [Working With Binary Data](#working-with-binary-data)
+  * [Rich Text Formatting](#rich-text-formatting)
+  * [Relative References in URLs](#relative-references-in-urls)
+  * [Schema](#schema-1)
+    * [OpenAPI Object](#openapi-object)
+    * [Info Object](#info-object)
+    * [Contact Object](#contact-object)
+    * [License Object](#license-object)
+    * [Server Object](#server-object)
+    * [Server Variable Object](#server-variable-object)
+    * [Components Object](#components-object)
+    * [Paths Object](#paths-object)
+    * [Path Item Object](#path-item-object)
+    * [Operation Object](#operation-object)
+    * [External Documentation Object](#external-documentation-object)
+    * [Parameter Object](#parameter-object)
+    * [Request Body Object](#request-body-object)
+    * [Media Type Object](#media-type-object)
+    * [Encoding Object](#encoding-object)
+    * [Responses Object](#responses-object)
+    * [Response Object](#response-object)
+    * [Callback Object](#callback-object)
+    * [Example Object](#example-object)
+    * [Working With Examples](#working-with-examples)
+    * [Link Object](#link-object)
+    * [Header Object](#header-object)
+    * [Tag Object](#tag-object)
+    * [Reference Object](#reference-object)
+    * [Schema Object](#schema-object)
+    * [Discriminator Object](#discriminator-object)
+    * [XML Object](#xml-object)
+    * [Security Scheme Object](#security-scheme-object)
+    * [OAuth Flows Object](#oauth-flows-object)
+    * [OAuth Flow Object](#oauth-flow-object)
+    * [Security Requirement Object](#security-requirement-object)
+  * [Specification Extensions](#specification-extensions)
+  * [Security Filtering](#security-filtering)
+* [Security Considerations](#security-considerations)
+  * [OpenAPI Document Formats](#openapi-document-formats)
+  * [Tooling and Usage Scenarios](#tooling-and-usage-scenarios)
+  * [Security Schemes](#security-schemes)
+  * [Handling External Resources](#handling-external-resources)
+  * [Markdown and HTML Sanitization](#markdown-and-html-sanitization)
+* [Appendix A: Revision History](#appendix-a-revision-history)
+* [Appendix B: Data Type Conversion](#appendix-b-data-type-conversion)
+* [Appendix C: Using RFC6570 Implementations](#appendix-c-using-rfc6570-implementations)
+  * [Equivalences Between Fields and RFC6570 Operators](#equivalences-between-fields-and-rfc6570-operators)
+  * [Non-RFC6570 Field Values and Combinations](#non-rfc6570-field-values-and-combinations)
+  * [Examples](#examples-3)
+    * [RFC6570-Equivalent Expansion](#rfc6570-equivalent-expansion)
+    * [Expansion With Non-RFC6570-Supported Options](#expansion-with-non-rfc6570-supported-options)
+    * [Undefined Values and Manual URI Template Construction](#undefined-values-and-manual-uri-template-construction)
+    * [Illegal Variable Names as Parameter Names](#illegal-variable-names-as-parameter-names)
+* [Appendix D: Serializing Headers and Cookies](#appendix-d-serializing-headers-and-cookies)
+* [Appendix E: Percent-Encoding and Form Media Types](#appendix-e-percent-encoding-and-form-media-types)
+  * [Percent-Encoding and `form-urlencoded`](#percent-encoding-and-form-urlencoded)
+  * [Percent-Encoding and `form-data`](#percent-encoding-and-form-data)
+  * [Generating and Validating URIs and `form-urlencoded` Strings](#generating-and-validating-uris-and-form-urlencoded-strings)
+    * [Interoperability with Historical Specifications](#interoperability-with-historical-specifications)
+    * [Interoperability with Web Browser Environments](#interoperability-with-web-browser-environments)
+  * [Decoding URIs and `form-urlencoded` Strings](#decoding-uris-and-form-urlencoded-strings)
+  * [Percent-Encoding and Illegal or Reserved Delimiters](#percent-encoding-and-illegal-or-reserved-delimiters)
+
+<!-- tocstop -->
+
 ## Definitions
 
 ### OpenAPI Description