Replaced group_by_namespace/1 by a call to maps:groups_from_list/2

* Since the bump to R25, group_by_namespace/1 follows only branch of the macro
* group_by_namespace/1 occurs once in apps/rebar/src/rebar_prv_completion.erl

apps/rebar/src/rebar_prv_completion.erl

@@ -56,7 +56,7 @@ do(State) ->
 
     Providers0 = rebar_state:providers(State),
     BareProviders = lists:filter(fun(P) -> provider_get(P, bare) end, Providers0),
-    ByNamespace = group_by_namespace(BareProviders),
+    ByNamespace = maps:groups_from_list(fun(P) -> provider_get(P, namespace) end, BareProviders),
     Cmds0 = maps:fold(
                 fun(NS,Ps,CmdAcc) -> namespace_to_cmpl_cmds(NS, Ps)++CmdAcc end,
                 [],
@@ -169,22 +169,6 @@ provider_get(P, short_desc) ->
 provider_get(P, namespace) ->
     element(12, P).
 
--if(?OTP_RELEASE >= 25).
-group_by_namespace(Ps) ->
-    maps:groups_from_list(fun(P) -> provider_get(P, namespace) end, Ps).
--else.
-group_by_namespace(Ps) ->
-    lists:foldl(fun(P, Acc) ->
-                    K=provider_get(P, namespace),
-                    case Acc of
-                        #{K:=Vs}->Acc#{K:=[P|Vs]};
-                        _ -> Acc#{K=>[P]}
-                    end
-                end,
-                #{},
-                Ps).
--endif.
-
 -spec format_error(any()) ->  iolist().
 format_error({error_writing_file,File,Err}) ->
     io_lib:format("Error occurred when trying to write into ~p file.~nReason: ~p~n", [File,Err]);