build: Don't remove generated docs on make clean
build: Don't remove generated docs on make clean

This should be removed by a (not yet implemented) distclean target.

ChrisCummins/chriscummins.cc,ChrisCummins/chriscummins.cc,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.github.io,ChrisCummins/chriscummins.cc,ChrisCummins/chriscummins.github.io