fix: correct test warning

Tests/SWXMLHashTests/XMLParsingTests.swift

@@ -201,7 +201,7 @@ struct XMLParsingTests {
                 case let elm as TextElement:
                     return acc + elm.text
                 default:
-                    #expect(false, "Unknown element type")
+                    Issue.record("Unknown element type")
                     return acc
                 }
             }