Increases berserker's rage lockout is back to 10 seconds (#6108)

# About the pull request

This PR reverts the rage lockout duration of Berserker back to 10
seconds.

# Explain why it's good for the game

Should help with punishing berserkers on their downtime, without
decreasing their effectiveness

# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>

Put screenshots and videos here with an empty line between the
screenshots and the `<details>` tags.

</details>


# Changelog
:cl:
balance: Berserker's rage lock-out duration increased slightly
/:cl:

code/modules/mob/living/carbon/xenomorph/strains/castes/ravager/berserker.dm

@@ -41,7 +41,7 @@
 
 	// Eviscerate config
 	var/rage_lock_duration = 10 SECONDS   // 10 seconds of max rage
-	var/rage_cooldown_duration = 8 SECONDS  // 8 seconds of NO rage.
+	var/rage_cooldown_duration = 10 SECONDS  // 10 seconds of NO rage.
 
 	// State for tracking rage
 	var/rage = 0