CQP & Poliqarp: Error for unknown flags

[margaretha]

Unknown flag such as the example below is just ignored in the serialization.

"Fraulein"%s

It would be more transparent and informative to throw an error g, e.g. Flag s is unknown.

A combination of known and unknown flags such as the example below:

"Fraulein"%cs

returns errors:

[302, "Failing to parse at symbol: '\"'", 13 ],
[ 302, "Could not parse query >>> \"Fraulein\"%cs <<<." ]

As the first example, an error should be thrown.

[margaretha]

[orth="l(au|ie)fen"%cd]
returns a warning

"warnings": [
    [
      748,
      "Flag is unknown",
      "flags:diacriticsInsensitive"
    ]
  ]