Function format_float_display 

pub fn format_float_display(value: f64) -> String

Format an f64 float for display, collapsing decimal artifacts.

Config floats backed by f32 (temperatures, thresholds) widen to long f64 tails (0.7 becomes 0.699999988079071) once serialized to toml::Value, and ±0.1 stepper presses accumulate similar tails (0.8 becomes 0.799999988079071). When the value round-trips exactly through f32, the shorter f32 form is displayed; otherwise a value within a tiny epsilon of a 1- or 2-decimal grid shows the grid form. Genuine precision is never rounded. Display-only: the stored value is untouched.

assert_eq!(format_float_display(0.699999988079071), "0.7");
assert_eq!(format_float_display(0.799999988079071), "0.8");
assert_eq!(format_float_display(0.3333333333333333), "0.3333333333333333");