Revamp errors in `aws-smithy-types-convert` and `aws-smithy-xml` (#1917)

...oftware/amazon/smithy/rustsdk/customize/s3/S3Decorator.kt

...zon/smithy/rust/codegen/core/smithy/protocols/AwsQuery.kt

...zon/smithy/rust/codegen/core/smithy/protocols/Ec2Query.kt

...azon/smithy/rust/codegen/core/smithy/protocols/RestXml.kt

...en/core/smithy/protocols/parse/AwsQueryParserGenerator.kt

...en/core/smithy/protocols/parse/Ec2QueryParserGenerator.kt

...gen/core/smithy/protocols/parse/RestXmlParserGenerator.kt

...e/smithy/protocols/parse/StructuredDataParserGenerator.kt

.../smithy/protocols/parse/XmlBindingTraitParserGenerator.kt

...rver/smithy/protocols/ServerHttpBoundProtocolGenerator.kt

rust-runtime/aws-smithy-http-server/src/rejection.rs

rust-runtime/aws-smithy-types-convert/src/date_time.rs

rust-runtime/aws-smithy-xml/src/decode.rs

rust-runtime/aws-smithy-xml/src/encode.rs

rust-runtime/aws-smithy-xml/src/unescape.rs

rust-runtime/aws-smithy-xml/tests/handwritten_parsers.rs

rust-runtime/aws-smithy-xml/tests/handwritten_serializers.rs

rust-runtime/inlineable/src/ec2_query_errors.rs

rust-runtime/inlineable/src/rest_xml_unwrapped_errors.rs

rust-runtime/inlineable/src/rest_xml_wrapped_errors.rs