Sphinx doesn't allow sections inside the function documentation and gives tons
of SEVERE warnings for them, so while just emphasizing the "Overload" header
is not ideal, it is better than before because at least the string "Overload"
itself appears in the Sphinx-generated output.
Update Doxygen-specific Python unit tests to work with the new indentation.
Update one of Doxygen-specific Java tests to still build with the new handling
of srcdir.