fs: write a better comment in step_into() concerning .mnt assignment

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260328175841.3390950-1-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: mjguzik

fs/namei.c

@@ -2141,7 +2141,7 @@ static __always_inline const char *step_into(struct nameidata *nd, int flags,
 		if (unlikely(!inode))
 			return ERR_PTR(-ENOENT);
 		nd->path.dentry = dentry;
-		/* nd->path.mnt is retained on purpose */
+		/* nd->path.mnt remains unchanged as no mount point was crossed */
 		nd->inode = inode;
 		nd->seq = nd->next_seq;
 		return NULL;