Documentation EXTENSION_MAPPING

Small addition of some missing "languages" in respect to EXTENSION_MAPPING.

src/config.xml

@@ -605,11 +605,11 @@ Go to the <a href="commands.html">next</a> section or return to the
  With this tag you can assign which parser to use for a given extension.
  Doxygen has a built-in mapping, but you can override or extend it using this tag.
  The format is <code>ext=language</code>, where \c ext is a file extension, and language is one of
- the parsers supported by doxygen: IDL, Java, Javascript, C#, C, C++, D, PHP,
- Objective-C, Python, Fortran (fixed format Fortran: FortranFixed,
+ the parsers supported by doxygen: IDL, Java, Javascript, Csharp (C#), C, C++, D, PHP,
+ md (Markdown), Objective-C, Python, Fortran (fixed format Fortran: FortranFixed,
  free formatted Fortran: FortranFree, unknown formatted Fortran: Fortran. In
  the later case the parser tries to guess whether the code is fixed or free
- formatted code, this is the default for Fortran type files), VHDL. 
+ formatted code, this is the default for Fortran type files), VHDL, tcl.
 
  For instance to make doxygen treat
  <code>.inc</code> files as Fortran files (default is PHP), and <code>.f</code> files as C (default is Fortran),