Fix building of documentation files.
Fix building of documentation files.

Apparently I never tested this back in 2014. The $(.TARGET:R) stuff is being
evaluated into nothing on my system and I have no idea where that extension
came from... So just type out the file names explicitly.

gencer/memcached,dormando/memcached,memcached/memcached,elfchief/memcached,memcached/memcached,gencer/memcached,elfchief/memcached,dormando/memcached,rmccullagh/memcached,bpzhang/memcached,samanbarghi/memcached,rmccullagh/memcached,rmccullagh/memcached,dormando/memcached,dormando/memcached,guikcd/memcached,bpzhang/memcached,elfchief/memcached,rmccullagh/memcached,samanbarghi/memcached,memcached/memcached,bpzhang/memcached,gencer/memcached,guikcd/memcached,gencer/memcached,memcached/memcached,memcached/memcached,rmccullagh/memcached,guikcd/memcached,samanbarghi/memcached,guikcd/memcached,samanbarghi/memcached,gencer/memcached,elfchief/memcached,dormando/memcached,elfchief/memcached,guikcd/memcached,bpzhang/memcached