Clamp before downcasting in float to i8 conversions

    Previously we were downcasting floats to the target type (e.g. int8_t), and then
    clamping to [-100, 100] range. This means that e.g. 129 would be cast to -127 and
    then converted to -100, in stead of becoming 100

    The fix does clamping first, and then casts the resulting number
    (which is guaranteed to be in range [-100, 100], due to clamping)
    from source type to target int8_t. Given the clamping, this will never overflow.

Author: Ngalstyan4

include/usearch/index_plugins.hpp

@@ -960,12 +960,13 @@ class i8_converted_t {
     inline explicit operator std::int32_t() const noexcept { return int8_; }
     inline explicit operator std::int64_t() const noexcept { return int8_; }
 
+    /* clamp uses std::less comparator which does not have comparisons for f16_t, so promoting v to float below */
     inline i8_converted_t(f16_t v)
-        : int8_(usearch::clamp<std::int8_t>(static_cast<std::int8_t>(v * divisor_k), min_k, max_k)) {}
+        : int8_(static_cast<std::int8_t>(usearch::clamp<f32_t>(v * divisor_k, min_k, max_k))) {}
     inline i8_converted_t(f32_t v)
-        : int8_(usearch::clamp<std::int8_t>(static_cast<std::int8_t>(v * divisor_k), min_k, max_k)) {}
+        : int8_(static_cast<std::int8_t>(usearch::clamp<f32_t>(v * divisor_k, min_k, max_k))) {}
     inline i8_converted_t(f64_t v)
-        : int8_(usearch::clamp<std::int8_t>(static_cast<std::int8_t>(v * divisor_k), min_k, max_k)) {}
+        : int8_(static_cast<std::int8_t>(usearch::clamp<f64_t>(v * divisor_k, min_k, max_k))) {}
 };
 
 f16_bits_t::f16_bits_t(i8_converted_t v) noexcept : uint16_(f32_to_f16(v)) {}