Meta: Generate correct format for user-variables.cmake

Author: https://github.com/bn3t 🔰
Commit: 02b5ab385a
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/5748

Meta/ladybird.py

@@ -240,9 +240,9 @@ def configure_skia_jemalloc() -> list[str]:
     with open(user_vars_cmake_module, "w") as f:
         f.writelines(
             [
-                f"set(PKGCONFIG {pkg_config})",
+                f"set(PKGCONFIG {pkg_config})\n",
-                f"set(GN {gn})",
+                f"set(GN {gn})\n",
-                "",
+                "\n",
             ]
         )