Add futhark-autotune to manpage index.
Add futhark-autotune to manpage index.

HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark,diku-dk/futhark,HIPERFIT/futhark,HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark