Loc_tree.of_ast: skip locations in doc-comments (#1404)
Loc_tree.of_ast: skip locations in doc-comments (#1404)

The `of_ast` function iterates on all locations and collects them in a
list. There is special code to replace to locations within doc-comments
to `Location.none`. But nothing will be done with these locations, so it
is possible to just cut the recursion by not calling the mapper to
collect locs under there.
ocaml-ppx/ocamlformat,ocaml-ppx/ocamlformat,ocaml-ppx/ocamlformat