RUST-294 remove unimplemented Display (#125)

Author: saghm

src/error.rs

@@ -172,7 +172,7 @@ pub enum ErrorKind {
 
     /// An error occurred when trying to execute a write operation
     #[error(
-        display = "An error occurred when trying to execute a write operation: {}",
+        display = "An error occurred when trying to execute a write operation: {:?}",
         _0
     )]
     WriteError(WriteFailure),
@@ -378,12 +378,6 @@ impl WriteFailure {
     }
 }
 
-impl fmt::Display for WriteFailure {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        unimplemented!()
-    }
-}
-
 /// Translates ErrorKind::BulkWriteError cases to ErrorKind::WriteErrors, leaving all other errors
 /// untouched.
 pub(crate) fn convert_bulk_errors(error: Error) -> Error {