Fix typo in memory usage docs

Author: ijjk

docs/02-app/01-building-your-application/06-optimizing/13-memory-usage.mdx

@@ -11,7 +11,7 @@ Let's explore some strategies and techniques to optimize memory and address comm
 
 Applications with a large amount of dependencies will use more memory.
 
-The [Bundle Analyzer](/docs/app/building-your-application/optimizing/bundle-analyzer) can help you investigate large dependencies in your application that may be able to be removed to improve performance and memory usage.
+The [Bundle Analyzer](/docs/app/building-your-application/optimizing/package-bundling#analyzing-javascript-bundles) can help you investigate large dependencies in your application that may be able to be removed to improve performance and memory usage.
 
 ## Run `next build` with `--experimental-debug-memory-usage`
 
@@ -72,11 +72,11 @@ const nextConfig = {
     config,
     { buildId, dev, isServer, defaultLoaders, nextRuntime, webpack }
   ) => {
-    if (cfg.cache && !dev) {
-      cfg.cache = Object.freeze({
+    if (config.cache && !dev) {
+      config.cache = Object.freeze({
         type: 'memory',
       })
-      cfg.cache.maxMemoryGenerations = 0
+      config.cache.maxMemoryGenerations = 0
     }
     // Important: return the modified config
     return config