ocamlformat

Prepare release 0.28.1

Merge branch 'MAIN' into pr/2706

in Bin_conf, discard *all* output from cmdliner Currently, Cmdliner is given a formatter that drops any text, but Cmdliner can (and does) print whitespace via the non-overridden out_spaces, out_indent and out_newlines.

make Ast_mapper iterate over all locations inside Longident.t These locations, which are new in 5.4, are sometimes traversed (e.g. Pexp_setfield) and sometimes not (e.g. Pexp_field). So clearly a bug. The fix is concretely: - change map_loc to map over both fields `{ loc; txt }` of `Location.loc` - propagate the change, ie change `map_loc` to `map_string_loc`, `map_string_opt_loc` or `map_loc_lid` depending on the type. All occurrences of the latter are bug fixes.