chore: made a comment more comprehensive

Author: nickytonline

test/rsc-data.spec.ts

@@ -28,7 +28,9 @@ describe('getRscDataRouter', () => {
     let rscDataRouter
 
     // Normally type checking would pick this up, but because this file is copied when generating
-    // edge functions for the build, I added a test
+    // edge functions for the build, we need to make sure it's valid for builds.
+    //
+    // See https://github.com/netlify/next-runtime/issues/1940
     expect(() => {
       rscDataRouter = getRscDataRouter(manifest)
     }).not.toThrow()