message: Fix bug where where format argument is not a literal string
diff: @@ -370,7 +370,7 @@ class JsonParserGenerator(
  if (StructureGenerator.fallibleBuilder(shape, symbolProvider)) {
  rustTemplate(
  """.map_err(|err| #{Error}::new(
  - #{ErrorReason}::Custom(format!({}, err).into()), None)
  + #{ErrorReason}::Custom(format!("{}", err).into()), None)
  )?""",
  *codegenScope
  )
  