--silent-prompt is now the same as --verbose

[leighklotz]

https://github.com/Mozilla-Ocho/llamafile/blob/956fb587b30f14c195465e7d281c5721767677bc/llama.cpp/common.cpp#L932

This may be a merge issue with llama.cpp; it looks like the commit that introduced --silent-prompt got only partially merged. https://github.com/Mozilla-Ocho/llamafile/commit/28d3160145e7595f84a9d7ec7f24e11ba153f796