Improve readability of sentence in partial-renderer docs [ci skip]
Merge pull request #12959 from macmartine/partial_renderer_doc_improvement

Improve readability of sentence in partial-renderer docs [ci skip]
Renderer#_render_template should be private

Closes #12831
Use the right indentation
_implied_layout_name should be private
Update caching guide with respect to :namespace

Cache::Store does not have a default value for :namespace. If it ever did, I can't find it in the git history.
Merge pull request #12961 from jbaudanza/doc

Update caching guide with respect to :namespace