Update warship instructions for veterancy (#4489)

## Description:

Adds simple help instructions for new warship veterancy to help screen.
Just to be clear about what levelling does and how many levels can be
achieved.
<img width="1136" height="388" alt="image"
src="https://github.com/user-attachments/assets/c14425b4-ea23-4b62-89b3-881f8c16e1f3"
/>


## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory

## Please put your Discord username so you can be contacted if a bug or
regression is found:

bijx

resources/lang/en.json

@@ -670,7 +670,7 @@
     "build_silo": "Missile Silo",
     "build_silo_desc": "Allows launching missiles.",
     "build_warship": "Warship",
-    "build_warship_desc": "Patrols in an area, capturing enemy trade ships and destroying their Boats (transport ships) and Warships. Spawns from the nearest Port and patrols the area you first clicked to build it. You can control Warships by attack-clicking on them (see action Attack under Hotkeys) and then attack-clicking the new area you want them to move to.",
+    "build_warship_desc": "Patrols in an area, capturing enemy trade ships and destroying their Boats (transport ships) and Warships. Spawns from the nearest Port and patrols the area you first clicked to build it. You can control Warships by attack-clicking on them (see action Attack under Hotkeys) and then attack-clicking the new area you want them to move to. Warships can level up (max level 3) by capturing enemy trade ships and destroying their transport boats and Warships. Leveling up increases the Warship's damage and health.",
     "drag": "drag",
     "exit_confirmation": "Are you sure you want to exit the game?",
     "game_id_tooltip": "Game ID",