quantize to F32/F16/Q8_0 can result in a Q6_K output tensor

[cebtenzzre]

Running quantize with a target dtype of F32, F16, or Q8_0 can result in a Q6_K output tensor without --pure (ref #5631 (comment)). This is surprising, as I would expect converting to F32 and then quantizing to F16 to produce similar results to converting directly to F16.

I suggest that the k-quant mixture logic should never attempt to decrease the quality of the output tensor, only increase it.

[cebtenzzre]

Fixed by ee35600