[DOCS] the an image in master_job_cache description shows an impossible config

[whytewolf]

Description the image at https://docs.saltproject.io/en/latest/topics/jobs/external_cache.html#master-job-cache-master-side-returner shows syslog being used as a master_job_cache. however because it is not possable to send and recive data from syslog as you would a database, syslog is not possable to be used as a master_job_cache.

The returner function for syslog also does not have the required functions for master_job_cache.

Suggested Fix remove syslog from the list in the master_job_cache picture.

Type of documentation image fix

Location or format of documentation https://docs.saltproject.io/en/latest/topics/jobs/external_cache.html#master-job-cache-master-side-returner

Additional context https://docs.saltproject.io/en/latest/_images/master-job-cache.png

[sagetherage]

Since the docs have incorrect information I am labeling this as a bug and high severity @ScriptAutomate