Remove incorrect tech requirement for Kushites

Naval Ballistae cannot be researched by the Kushites, who don't have
access to siege ships. Hence their unique Flaming Projectiles technology
cannot depend upon Naval Ballistae.

This removes the dependency and increases the cost of the unique tech.

Fixes: #8046
Patch-By: rene
Reviewed-By: Itms
Reviewed-At: https://gitea.wildfiregames.com/0ad/0ad/pulls/8056

binaries/data/mods/public/gui/credits/texts/balancing.json

@@ -35,6 +35,7 @@
 				{ "nick": "Pureon" },
 				{ "nick": "quantumstate", "name": "Jonathan Waller" },
 				{ "nick": "real_tabasco_sauce" },
+				{ "nick": "rene" },
 				{ "nick": "sanderd17", "name": "Sander Deryckere" },
 				{ "nick": "scythetwirler", "name": "Casey X." },
 				{ "nick": "Stan", "name": "Stanislas Dolcini" },

binaries/data/mods/public/simulation/data/technologies/warship_ranged_attack.json

@@ -1,9 +1,9 @@
 {
-	"supersedes": "warship_siege_attack",
 	"genericName": "Flaming Projectiles",
 	"description": "Flaming munitions were very useful against wooden targets such as ships.",
 	"cost": {
-		"wood": 800
+		"wood": 1200,
+		"metal": 400
 	},
 	"requirements": {
 		"all": [
@@ -15,7 +15,7 @@
 			}
 		]
 	},
-	"requirementsTooltip": "Unlocked in City Phase. Requires “Naval Ballistae.”",
+	"requirementsTooltip": "Unlocked in City Phase.",
 	"icon": "fire_arrows.png",
 	"researchTime": 40,
 	"tooltip": "Ranged Warships +10% attack damage.",