doc comments

Author: tnuha

library/std/src/ffi/os_str.rs

@@ -558,6 +558,9 @@ impl OsString {
         self.inner.as_mut_vec_for_path_buf()
     }
 
+    /// More well behaving alternative to allowing outer types
+    /// full mutable access to the core `Vec`.
+    /// Provides plumbing to core `Vec::truncate`.
     #[inline]
     pub(crate) fn truncate(&mut self, len: usize) {
         self.inner.truncate(len);

library/std/src/sys/os_str/bytes.rs

@@ -208,6 +208,9 @@ impl Buf {
         &mut self.inner
     }
 
+    /// More well behaving alternative to allowing outer types
+    /// full mutable access to the core `Vec`.
+    /// Provides plumbing to core `Vec::truncate`.
     #[inline]
     pub(crate) fn truncate(&mut self, len: usize) {
         self.inner.truncate(len);