Provide a way to identify function overloads.

[purpleKarrot]

In the doxygen generated XML output, the only way to find out whether a function is overloaded or not, is to compare the description with the following string: "This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts."

See here for example: https://github.com/boostorg/boostbook/blob/develop/xsl/doxygen/doxygen2boostbook.xsl#L22

It would be nice if doxypress provided a better way.