message: Fix overlapping patterns
diff: @@ -170,8 +170,8 @@ impl<W: Write> PNMEncoder<W> {
  let (maxval, tupltype) = match color {
  ColorType::Gray(1) => (1, ArbitraryTuplType::BlackAndWhite),
  ColorType::GrayA(1) => (1, ArbitraryTuplType::BlackAndWhiteAlpha),
  - ColorType::Gray(n @ 1..=16) => ((1 << n) - 1, ArbitraryTuplType::Grayscale),
  - ColorType::GrayA(n @ 1..=16) => ((1 << n) - 1, ArbitraryTuplType::GrayscaleAlpha),
  + ColorType::Gray(n @ 2..=16) => ((1 << n) - 1, ArbitraryTuplType::Grayscale),
  + ColorType::GrayA(n @ 2..=16) => ((1 << n) - 1, ArbitraryTuplType::GrayscaleAlpha),
  ColorType::RGB(n @ 1..=16) => ((1 << n) - 1, ArbitraryTuplType::RGB),
  ColorType::RGBA(n @ 1..=16) => ((1 << n) - 1, ArbitraryTuplType::RGBAlpha),
  _ => {
  