Add a blank line between error message and reference link

I think this makes the error message stand out a little better and more readable.

Author: per1234

main.go

@@ -260,7 +260,7 @@ func populateSubmission(submissionURL string, listPath *paths.Path) (submissionT
 
 	// Check if URL is from a supported Git host.
 	if !uRLIsUnder(normalizedURLObject, supportedHosts) {
-		submission.Error = normalizedURLObject.Host + " is not currently supported as a Git hosting website for Library Manager.%0ASee: https://github.com/arduino/library-registry/blob/main/FAQ.md#what-are-the-requirements-for-a-library-to-be-added-to-library-manager"
+		submission.Error = normalizedURLObject.Host + " is not currently supported as a Git hosting website for Library Manager.%0A%0ASee: https://github.com/arduino/library-registry/blob/main/FAQ.md#what-are-the-requirements-for-a-library-to-be-added-to-library-manager"
 		return submission, ""
 	}
 

test/test_all.py

@@ -91,8 +91,8 @@
                     "official": False,
                     "tag": "",
                     "error": "example.com is not currently supported as a Git hosting website for Library Manager.%0A"
-                    "See: https://github.com/arduino/library-registry/blob/main/FAQ.md#what-are-the-requirements-for-a-"
-                    "library-to-be-added-to-library-manager",
+                    "%0ASee: https://github.com/arduino/library-registry/blob/main/FAQ.md#what-are-the-requirements-for"
+                    "-a-library-to-be-added-to-library-manager",
                 }
             ],
             "",