chore: remove 'upstream' reference — describe behavior directly

Author: johanrd

lib/rules/template-no-whitespace-for-layout.js

@@ -27,10 +27,10 @@ module.exports = {
 
     return {
       GlimmerTextNode(node) {
-        // Upstream ember-template-lint only visits body text; its HBS parser
-        // exposes attribute values as strings rather than TextNode children.
-        // ember-eslint-parser emits them as GlimmerTextNode children of a
-        // GlimmerAttrNode, so skip those to match upstream scope.
+        // Only flag body text, not attribute values. ember-eslint-parser
+        // emits attribute values as GlimmerTextNode children of a
+        // GlimmerAttrNode; skip those so only element body whitespace is
+        // checked.
         if (node.parent?.type === 'GlimmerAttrNode') {
           return;
         }