This commit introduces another `extract::path::ErrorKind` variant that captures the
serde error nominally captured through the `serde::de::Error` trait impl on `PathDeserializeError`.
We augment the deserialization error with the captured (key, value), allowing `extract::Path`, and wrapping
extractors, to gain programmatic access to the key name, and attempted deserialized value.
The `PathDeserializationError::custom` is used two places in addition to capture the deserialization error.
These usages should still be unaffected.
Co-authored-by: David Mládek <[email protected]>