Add doc-building to CI script
Add doc-building to CI script

ihc/futhark,diku-dk/futhark,mrakgr/futhark,diku-dk/futhark,HIPERFIT/futhark,diku-dk/futhark,ihc/futhark,CulpaBS/wbBach,HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark,mrakgr/futhark,mrakgr/futhark,HIPERFIT/futhark,ihc/futhark