dune_rule_gen: stop considering .aux as targets
dune_rule_gen: stop considering .aux as targets

They may cause cache issues

See also https://github.com/ocaml/dune/pull/6024

SkySkimmer/coq,coq/coq,SkySkimmer/coq,SkySkimmer/coq,ejgallego/coq,SkySkimmer/coq,coq/coq,ejgallego/coq,ejgallego/coq,ejgallego/coq,coq/coq,coq/coq