fix: typo "fr" (#2274)

Author: linsyking

src/sys/stat.rs

@@ -39,7 +39,7 @@ libc_bitflags! {
         S_IXUSR;
         /// Read write and execute for group.
         S_IRWXG;
-        /// Read fr group.
+        /// Read for group.
         S_IRGRP;
         /// Write for group.
         S_IWGRP;
@@ -454,4 +454,4 @@ pub fn mkdirat<P: ?Sized + NixPath>(
     })?;
 
     Errno::result(res).map(drop)
-}
+}