linuxHeaders_5_19: init at 5.19.16

Maybe multiple packages might use this temporarily,
e.g. due "flexible array member" errors - consequence of:
https://github.com/torvalds/linux/commit/94dfc73e7cf4a31da66b8843f0b9283ddd6b8381

pkgs/top-level/all-packages.nix

···
   inherit (callPackages ../os-specific/linux/kernel-headers { })
     linuxHeaders makeLinuxHeaders;
 
+  linuxHeaders_5_19 = linuxHeaders.overrideAttrs (_: rec {
+    version = "5.19.16";
+    src = fetchurl {
+      url = "mirror://kernel/linux/kernel/v5.x/linux-${version}.tar.xz";
+      sha256 = "13g0c6ljxk3sd0ja39ndih5vrzp2ssj78qxaf8nswn8hgrkazsx1";
+    };
+  });
+
   klibc = callPackage ../os-specific/linux/klibc { };
 
   klibcShrunk = lowPrio (callPackage ../os-specific/linux/klibc/shrunk.nix { });