[docs] FileStore does not implement local store

Oversight in https://github.com/rails/rails/pull/42626

activesupport/lib/active_support/cache/file_store.rb

@@ -7,9 +7,6 @@ require "uri/common"
 module ActiveSupport
   module Cache
     # A cache store implementation which stores everything on the filesystem.
-    #
-    # FileStore implements the Strategy::LocalCache strategy which implements
-    # an in-memory cache inside of a block.
     class FileStore < Store
       attr_reader :cache_path