Fix: Off by one error

When printing the error chain, we print the error and then iterate over
the causes. Hence, we have to increase the printed number by one here,
because 0 (zero) is already printed.

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

lib/core/libimagerror/src/trace.rs

@@ -41,7 +41,7 @@ impl<'a> Display for ImagTrace<'a, Error>
             for (i, cause) in self.0.iter_causes().enumerate() {
                 let _ = writeln!(fmt,
                                  "{prefix}: {error}",
-                                 prefix = Red.blink().paint(format!("ERROR[{:>4}]", i)),
+                                 prefix = Red.blink().paint(format!("ERROR[{:>4}]", i + 1)),
                                  error = cause)?;
             }
         }