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##### SUMMARY
<!--- Explain the problem briefly below -->
Ansible documents a fact_caching_prefix option for the jsonfile cache plugin. It does not appear to do anything. Also, the fact_caching_connection option is documented as `_uri` rather than `_connection`.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
jsonfile

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.9.8
  config file = /home/mark/src/ansible/ansible2/ansible.cfg
  configured module search path = [u'/home/mark/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /home/mark/src/ansible-playground/venv-2.9/local/lib/python2.7/site-packages/ansible
  executable location = /home/mark/src/ansible-playground/venv-2.9/bin/ansible
  python version = 2.7.12 (default, Oct  8 2019, 14:14:10) [GCC 5.4.0 20160609]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below

```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
Ubuntu

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

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##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->


##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below

```

"""
    This is for backwards compatibility.  Will be removed after deprecation.  It was removed as it
    wasn't actually part of the cache plugin API.  It's actually the code to make use of cache
    plugins, not the cache plugin itself.  Subclassing it wouldn't yield a usable Cache Plugin and
    there was no facility to use it as anything else.
    """
    def __init__(self, *args, **kwargs):
        display.deprecated('ansible.plugins.cache.FactCache has been moved to'
                           ' ansible.vars.fact_cache.FactCache.  If you are looking for the class'
                           ' to subclass for a cache plugin, you want'
                           ' ansible.plugins.cache.BaseCacheModule or one of its subclasses.',
                           version='2.12', collection_name='ansible.builtin')
        super(FactCache, self).__init__(*args, **kwargs)
class BaseCacheModule(AnsiblePlugin):