DOC: config: move the cache-use and cache-store actions to the proper section

DOC: config: move the cache-use and cache-store actions to the proper section

Actions were grouped by previous commit d54e8f810 ("DOC: config: reorganize
actions into their own section") but cache-use and cache-store were still
making reference to the cache section. This moves the text back to their
respective keywords in the actions section and leaves the example and an
explanation of how to use the keywords in the cache section.