Skip private fields in Lua generator

A lot of the newer Paper and Adventure API have public methods the same name as private fields and the Lua LS doesn't know how to deal with a field the same name as a method

Author: Saturn745

src/main/kotlin/generator/LuaEmitter.kt

@@ -19,6 +19,8 @@ class LuaEmitter {
 
         // Process fields (variables)
         parsedClass.fields.forEach { field ->
+            // Skip private fields
+            if (field.visibility == Visibility.PRIVATE) return@forEach
             sb.appendLine(
                 "---@field ${
                     field.visibility.toString().lowercase()