fix: do not split quoted key as path

[zmstone]

fixes #269

[thalesmg]

I suggest adding the following test case:

map_with_placeholders_test() ->
    RawConf =
        #{ <<"headers">> =>
               #{
                 <<"fixed_key">> => <<"fixed_value">>,
                 <<"${.payload.key}">> => <<"fixed_value">>,
                 <<"${.payload.key}2">> => <<"${.payload.value}">>,
                 <<"fixed_key2">> => <<"${.payload.value}">>
                }
         },
    TmpFile = "/tmp/" ++ atom_to_list(?FUNCTION_NAME) ++ ".conf",
    try
        ok = file:write_file(TmpFile, hocon_pp:do(RawConf, #{})),
        {ok, LoadedConf} = hocon:load(TmpFile, #{format => map}),
        ?assertEqual(RawConf, LoadedConf),
        ok
    after
        file:delete(TmpFile)
    end.

[zmstone]

tagged: 0.39.17