Clarify Timer precision

Author: ivmarkov

src/timer.rs

@@ -15,10 +15,14 @@ use std::time::Instant;
 /// # Precision
 ///
 /// There is a limit on the maximum precision that a `Timer` can provide. This limit is
-/// dependent on the current platform; for instance, on Windows, the maximum precision is
+/// dependent on the current platform and follows the precision provided by the `embassy-time`
+/// crate for that platform; for instance, on Windows, the maximum precision is
 /// about 16 milliseconds. Because of this limit, the timer may sleep for longer than the
 /// requested duration. It will never sleep for less.
 ///
+/// On embedded platforms like ESP-IDF, the precision is much higer (up to 1 microsecond),
+/// because the `embassy-time` crate for ESP-IDF uses the ESP-IDF Timer service.
+///
 /// # Examples
 ///
 /// Sleep for 1 second: