Stub out all appendix headers (3.0.4)

So that additional PRs can avoid merge conflicts.

versions/3.0.4.md

@@ -3697,6 +3697,10 @@ Version   | Date       | Notes
 1.1       | 2012-08-22 | Release of Swagger 1.1
 1.0       | 2011-08-10 | First release of the Swagger Specification
 
+## <a name="dataTypeConversion"></a>Appendix B: Data Type Conversion
+
 ## <a name="usingRFC6570Implementations"></a>Appendix C: Using RFC6570 Implementations
 
 ## <a name="serializingHeadersAndCookies"></a>Appendix D: Serializing Headers and Cookies
+
+## <a name="percentEncodingAndFormMediaTypes"></a>Appendix E: Percent-Encoding and Form Media Types