fix: convert default border image formatting errors

Author: intellild

src/properties/border_image.rs

@@ -301,7 +301,8 @@ impl<'i> BorderImage<'i> {
 
     // A shorthand with only initial components must still have a value.
     if !has_source && !has_slice && !has_width && !has_outset && !has_repeat {
-      return dest.write_str("none");
+      dest.write_str("none")?;
+      return Ok(());
     }
 
     if has_source {