fix: trim URIs

URIs used for namespaces must be trimmed. The algorithm to check for
duplicate attributes needs to not be thrown off by spaces before or
after the URIs. We also record them trimmed in the data we pass to
events handlers.

lib/saxes.js

@@ -885,9 +885,11 @@ class SAXParser {
 
       let { ns } = tag;
       let disconnectedNS = false;
-      for (const [name, uri] of this.attribList) {
+      // eslint-disable-next-line prefer-const
+      for (let [name, uri] of this.attribList) {
         const { prefix, local } = this.qname(name, true);
         if (prefix === "xmlns") {
+          uri = uri.trim();
           // namespace binding attribute. push the binding into scope
           if (local === "xml" && uri !== XML_NAMESPACE) {
             this.fail(`xml: prefix must be bound to ${XML_NAMESPACE}\n` +