This regex is too complex for bash's own replacement. Add ignore for the shellcheck rule.

Signed-off-by: DL6ER <dl6er@dl6er.de>

advanced/Scripts/webpage.sh

@@ -236,6 +236,7 @@ trust-anchor=.,20326,8,2,E06D44B80B8F1D39A95C0B0D7C65D08458E880409BBC68345710423
         else
             # Something else, convert to /24 subnet (preserves legacy behavior)
             # This sed converts "192.168.1.2" to "192.168.1.0/24"
+            # shellcheck disable=2001
             REV_SERVER_CIDR="$(sed "s+\\.[0-9]*$+\\.0/24+" <<< "${REV_SERVER_TARGET}")"
         fi
         add_setting "REV_SERVER_CIDR" "${REV_SERVER_CIDR}"