Fix div_duration() marked as stable by mistake

Author: JMS55

posts/2019-09-26-Rust-1.38.0.md

@@ -95,8 +95,8 @@ Additionally, these functions have been stabilized:
 
 - [`<*const T>::cast`] and [`<*mut T>::cast`]
 - [`Duration::as_secs_f32`] and [`Duration::as_secs_f64`]
-- [`Duration::div_duration_f32`] and [`Duration::div_duration_f64`]
-- [`Duration::div_f32`] and [`Duration::div_f64`]
+- EDIT: A Previous version of this post mistakenly marked these as stable.
+- ~~[`Duration::div_duration_f32`] and [`Duration::div_duration_f64`]~~- [`Duration::div_f32`] and [`Duration::div_f64`]
 - [`Duration::from_secs_f32`] and [`Duration::from_secs_f64`]
 - [`Duration::mul_f32`] and [`Duration::mul_f64`]
 - Euclidean remainder and division operations -- [`div_euclid`],