## What changes were proposed in this pull request?

Minor doc fix regarding the spark.speculation.quantile configuration parameter.  It incorrectly states it should be a percentage, when it should be a fraction.

## How was this patch tested?

(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)

(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)

I tried building the documentation but got some unidoc errors.  I also got them when building off origin/master, so I don't think I caused that problem.  I did run the web app and saw the changes reflected as expected.

Author: Nicholas Brown <nbrown@adroitdigital.com>

Closes #14352 from nwbvt/master.