fix: doctests

Author: conradludgate

library/std/src/ffi/os_str.rs

@@ -637,9 +637,10 @@ impl OsStr {
     /// # Examples
     ///
     /// ```
+    /// #![feature(const_path)]
     /// use std::ffi::OsStr;
     ///
-    /// const OS_STR: OsStr = OsStr::from_str("foo");
+    /// const OS_STR: &OsStr = OsStr::from_str("foo");
     /// ```
     #[inline]
     #[unstable(feature = "const_path", reason = "TBD", issue = "none")]

library/std/src/path.rs

@@ -1959,10 +1959,11 @@ impl Path {
     /// # Examples
     ///
     /// ```
+    /// #![feature(const_path)]
     /// use std::ffi::OsStr;
     /// use std::path::Path;
     ///
-    /// const PATH: Path = Path::from_os_str(OsStr::from_str("/foo/bar"));
+    /// const PATH: &Path = Path::from_os_str(OsStr::from_str("/foo/bar"));
     /// ```
     #[inline]
     #[unstable(feature = "const_path", reason = "TBD", issue = "none")]