Fix mistyped closing </span> tag (was <span>)

src/v1/parsedToTree.ts

@@ -138,7 +138,7 @@ export class ParsedTreeHandler {
 
             return s`${text}`;
         } else if (exported.type === ObjectType.Undefined) {
-            return s`<span class="missing">${"<no value>"}<span>`;
+            return s`<span class="missing">${"<no value>"}</span>`;
         } else
             throw new Error(`primitiveToText: object is not primitive: ${exported.type}!`);
     }