make the output of "show api dump file <filename> compare-current" doxygen-friendly
make the output of "show api dump file <filename> compare-current" doxygen-friendly

The current output of the API diff requires some massaging
to appear like a table in the docs generated by doxygen.
This change eliminates this need.

Change-Id: Ic9269a0e5e232e4d01a0695561e4f90eee287327
Signed-off-by: Andrew Yourtchenko <eb6233fe2fbd585844f4fb8426b53b186ab379b1@gmail.com>

chrisy/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,chrisy/vpp,vpp-dev/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,vpp-dev/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp