refactor: improve game icon validation script

The commit refactors the game icon validation script to improve its functionality. It adds a check for unexpected game icons and ensures that the number of game icons matches the number of servers in serverlist.csv. The commit also updates error messages for better clarity and readability.

.github/workflows/serverlist-validate-game-icons.sh

@@ -14,13 +14,25 @@ for shortname in $(tail -n +2 serverlist.csv | cut -d ',' -f1); do
 	fi
 done
 
+echo ""
+echo "Checking if an unexpected gameicon exists"
+for gameicon in $(ls -1 gameicons); do
+	# check if $gameicon is in serverlist.csv
+	if ! grep -q "${gameicon%-icon.png}" serverlist.csv; then
+		echo "ERROR: gameicon ${gameicon} is not in serverlist.csv"
+		exitcode=1
+	else
+		echo "OK: gameicon ${gameicon} is in serverlist.csv"
+	fi
+done
+
 # check that the number of gameicons matches the number of servers in serverlist.csv
 echo ""
 echo "Checking that the number of gameicons matches the number of servers in serverlist.csv"
 gameiconcount="$(ls -1 gameicons | wc -l)"
 serverlistcount="$(tail -n +2 serverlist.csv | wc -l)"
 if [ "${gameiconcount}" -ne "${serverlistcount}" ]; then
-	echo "ERROR: game icons (${gameiconcount}) does not match serverlistcount ($serverlistcount)"
+	echo "ERROR: game icons (${gameiconcount}) does not match serverlist.csv ($serverlistcount)"
 	exitcode=1
 else
 	echo "OK: gameiconcount ($gameiconcount) matches serverlistcount ($serverlistcount)"