graph: Add '--max-depth'....* guix/graph.scm (export-graph): Add #:max-depth and honor it, adding
'depths' argument to 'loop'.
* guix/scripts/graph.scm (%options, show-help): Add '--max-depth'.
(%default-options): Add 'max-depth'.
(guix-graph): Pass #:max-depth to 'export-graph'.
* tests/graph.scm ("package DAG, limited depth"): New test.
* doc/guix.texi (Invoking guix graph): Document it.
Ludovic Courtès
2020-10-20
graph: Adjust test for recent OCaml changes....This is a followup to 339177956affdc471832750a3805b74356487e93.
* tests/graph.scm ("reverse bag DAG"): Look for "ocaml4.07-dune" rather
than "dune".