dimIndex does not get parsed correctly in .svd files

[DNedic]

While updating the ESP32-C3 .svd file, I noticed that register groups that had dimIndex fields added were suddenly missing in chip.zig and were replaced with reserved fields.

To reproduce, replace the ESP32-C3 .svd file with one found in the esp-pacs repo, or patch it and use the patched version and re-build and check the GPIO.PINn registers.