video_codec: update JPEG_XS metadata

- FourCC - 'JXSS' seem to be the right one to use (although very little
references available)
- short name - replace space with underscore - compliant with other codecs
(not using spaces) - maybe even JXS would be better?
- extension - .jxs seem to be used almost exclusively (wiki doesn't mention
any other)

src/video_codec.c

@@ -13,7 +13,7 @@
  * This file contains video codecs' metadata and helper
  * functions.
  */
-/* Copyright (c) 2005-2025 CESNET
+/* Copyright (c) 2005-2026 CESNET, zájmové sdružení právnických osob
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, is permitted provided that the following conditions
@@ -151,8 +151,8 @@ static const struct codec_info_t codec_info[] = {
                 to_fourcc('R','G','B','2'), 3, 1, 1, 8, VCF_RGB, SUBS_444, "rgb"},
         [JPEG] = {"JPEG",  "JPEG",
                 to_fourcc('J','P','E','G'), 1, 1, 0, 8, VCF_NONE, VC_OPAQUE, "jpg"},
-        [JPEG_XS] = {"JPEG XS", "JPEG XS",
-                to_fourcc('J', 'P', 'X', 'S'), 1, 1, 0, 8, VCF_NONE, VC_OPAQUE, "jpegxs"},
+        [JPEG_XS] = {"JPEG_XS", "JPEG XS",
+                to_fourcc('J', 'X', 'S', 'S'), 1, 1, 0, 8, VCF_NONE, VC_OPAQUE, "jxs"},
         [RAW] = {"raw", "Raw SDI video",
                 to_fourcc('r','a','w','s'), 1, 1, 0, 0, VCF_NONE, VC_OPAQUE, "raw"}, /* raw SDI */
         [H264] = {"H.264", "H.264/AVC",