Help text: Retain X amount of log entries

In light of comment #6 detail explaining the number of log entries saved is multiplied by the number of cron tasks the site is running, my suggestion is to make this info clear in the help text for the setting.

For example, it currently says, "Retain X amount of log entries." and my suggested edit would be "Retain X amount of log entries; this value is per cron job. Setting this to 1000 on sites with 15 cron jobs will store a total of 15000 entries. High values can result in slower log performance."