Double space in async trait docs generated by decl_threshold_traits!

Problem

In embedded-sensors/src/sensor.rs, the blocking arm passes doc_suffix = "synchronously" while the async arm passes doc_suffix = " asynchronously" - with a leading space. The surrounding concat! already inserts the separating space, so every async-generated trait doc renders with a double space:

Set Temperature thresholds  asynchronously.

Suggested fix

Drop the leading space from the async doc_suffix.

Related nit (same code path)

stringify!($SensorName) produces the un-spaced identifier, so docs read "Set RelativeHumidity thresholds ..." rather than "Set relative humidity thresholds ...". Consider threading a separate human-readable $display_name string literal through the macro alongside $unit.

Open embedded-sensors/src/sensor.rs and inspect the blocking and async arms of decl_threshold_traits!. Start by comparing their doc_suffix values. Done means the async-generated trait documentation renders with a single space, with the related human-readable sensor-name improvement considered separately.