Updated text for retention bonuses option

The existing description for the retention bonuses option in the campaign options dialog was modified. "Pay Bonuses by Default" was replaced with "Automate Retention Bonuses" for clearer understanding.

MekHQ/resources/mekhq/resources/CampaignOptionsDialog.properties

@@ -157,7 +157,7 @@ lblServiceContractDuration.text=Service Contract Duration
 lblServiceContractDuration.toolTipText=Once recruited, this is the minimum amount of months personnel will remain with the unit (set to 0 to disable service contracts).
 lblServiceContractModifier.text=Service Contract Modifier
 lblServiceContractModifier.toolTipText=While personnel are under contract, this value reduces their Turnover target number.
-chkPayBonusDefault.text=Pay Bonuses by Default
+chkPayBonusDefault.text=Automate Retention Bonuses
 chkPayBonusDefault.toolTipText=Personnel with a turnover target number equal (or exceeding) the below threshold will have their retention bonus paid by default.
 lblPayBonusDefaultThreshold.text=Bonus Threshold
 lblPayBonusDefaultThreshold.toolTipText=This option sets the threshold for default bonus payouts (if the above option is enabled).