fix: make xmake rex options consistent

Author: shad0wshayd3

xmake.lua

@@ -15,23 +15,23 @@ add_rules("mode.debug", "mode.releasedbg")
 includes("xmake-rules.lua")
 
 -- define options
-option("rex_ini")
+option("rex_ini", function()
     set_default(false)
     set_description("Enable ini config support for REX")
     add_defines("REX_OPTION_INI=1")
-option_end()
+end)
 
-option("rex_json")
+option("rex_json", function()
     set_default(false)
     set_description("Enable json config support for REX")
     add_defines("REX_OPTION_JSON=1")
-option_end()
+end)
 
-option("rex_toml")
+option("rex_toml", function()
     set_default(false)
     set_description("Enable toml config support for REX")
     add_defines("REX_OPTION_TOML=1")
-option_end()
+end)
 
 option("skyrim_ae", function()
     set_default(false)