(fix) Check if the returned textmap is null

src/main/java/emu/lunarcore/util/Handbook.java

@@ -27,7 +27,11 @@ public class Handbook {
         try {
             textMap = JsonUtils.loadToMap(LunarCore.getConfig().getResourceDir() + "/TextMap/TextMap" + language + ".json", Long.class, String.class);
         } catch (Exception e) {
-            e.printStackTrace();
+            LunarCore.getLogger().error("Error loading text map: " + language, e);
+            return;
+        }
+
+        if (textMap == null) {
             return;
         }