io: Remove redundant requirement on Debug

core::error::Error already depends on Debug, thus this is a compatible
simplification.

Author: chrysn

embedded-io/src/lib.rs

@@ -172,7 +172,7 @@ impl From<std::io::ErrorKind> for ErrorKind {
 ///
 /// This trait allows generic code to do limited inspecting of errors,
 /// to react differently to different kinds.
-pub trait Error: fmt::Debug + core::error::Error {
+pub trait Error: core::error::Error {
     /// Get the kind of this error.
     fn kind(&self) -> ErrorKind;
 }