Correct example value for spark.ssl.YYY.XXX settings
Correct example value for spark.ssl.YYY.XXX settings

Docs adjustment to:
- link to other relevant section of docs
- correct statement about the only value when actually other values are supported

Author: Andrew Ash <andrew@andrewash.com>

Closes #14581 from ash211/patch-10.

(cherry picked from commit 8a6b7037bb058d00cc767895c3292509576ea2f9)
Signed-off-by: Sean Owen <291c18f3fb7528c712d9098b0e50a515ea0b91d5@cloudera.com>

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