Chore: Fix misleading comment in ConfigCache.js (#8799)

In a previous iteration of the glob config implementation, the ConfigCache class was not exported from its module. However, now it is exported. This commit removes an outdated comment that stated the opposite.

lib/config/config-cache.js

@@ -24,9 +24,9 @@ function hash(vector) {
 //------------------------------------------------------------------------------
 
 /**
- * Configuration caching class (not exported)
+ * Configuration caching class
  */
-class ConfigCache {
+module.exports = class ConfigCache {
 
     constructor() {
         this.filePathCache = new Map();
@@ -125,6 +125,4 @@ class ConfigCache {
     setMergedConfig(vector, config) {
         this.mergedCache.set(hash(vector), config);
     }
-}
-
-module.exports = ConfigCache;
+};