Merge pull request #47225 from runephilosof-karnovgroup/patch-1

Document `namespace` option for read method

activesupport/lib/active_support/cache.rb

@@ -394,6 +394,7 @@ module ActiveSupport
       #
       # ==== Options
       #
+      # * +:namespace+ - Replace the store namespace for this call.
       # * +:version+ - Specifies a version for the cache entry. If the cached
       #   version does not match the requested version, the read will be treated
       #   as a cache miss. This feature is used to support recyclable cache keys.