[DevTools][Bugfix] Don't hide fragment if it has a key (facebook#25197)

resolves facebook#25187

---

We shouldn't hide fragments that have a key because this is important information that the user might want in the future.

packages/react-devtools-shared/src/backend/renderer.js

@@ -468,8 +468,9 @@ export function getInternalReactConstants(
         return type;
       case HostPortal:
       case HostText:
-      case Fragment:
         return null;
+      case Fragment:
+        return 'Fragment';
       case LazyComponent:
         // This display name will not be user visible.
         // Once a Lazy component loads its inner component, React replaces the tag and type.
@@ -981,7 +982,7 @@ export function attach(
 
   // NOTICE Keep in sync with get*ForFiber methods
   function shouldFilterFiber(fiber: Fiber): boolean {
-    const {_debugSource, tag, type} = fiber;
+    const {_debugSource, tag, type, key} = fiber;
 
     switch (tag) {
       case DehydratedSuspenseComponent:
@@ -993,13 +994,14 @@ export function attach(
         return true;
       case HostPortal:
       case HostText:
-      case Fragment:
       case LegacyHiddenComponent:
       case OffscreenComponent:
         return true;
       case HostRoot:
         // It is never valid to filter the root element.
         return false;
+      case Fragment:
+        return key === null;
       default:
         const typeSymbol = getTypeSymbol(type);