Fix a display issue in the documentation for tjDecompress2() (doxygen treats a star...

Fix a display issue in the documentation for tjDecompress2() (doxygen treats a star at the beginning of the line as a list bullet);  make the documentation more readable by displaying fixed-width text (which is used to refer to variables and functions) in a different color.

git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1338 632fc199-4ca6-4c93-a231-07263d6284db