Add error trait to error type.

gamelog/src/error.rs

@@ -18,6 +18,8 @@ impl fmt::Display for LogFileError {
     }
 }
 
+impl std::error::Error for LogFileError {}
+
 impl From<SpannedError> for LogFileError {
     fn from(value: SpannedError) -> Self {
         Self::RonSpanned(value)