Add OpenGL ES Shading Language and glTF 2.0

[tidoust]

This adds 2 additional specifications developed by the Khronos Group, as requested in #1089, and adjusts the code that was a bit too specific to WebGL specs and extensions accordingly.

The notion of "Working Group" within the Khronos Group appears somewhat informal, but the terminology is used in the page that lists Working Group officers at least: https://www.khronos.org/about/working-group-officers/

Issue #1089 mentions GLSL, and not OpenGL ES Shading Language, but the latter is what WebGL uses, and so should be what browsers implement. The name ESSL is the official name for the ES variant, see: https://github.com/KhronosGroup/GLSL

That repository only contains extensions and the issue tracker for the GLSL and ESSL specifications, but not the actual specifications. I did not set the nightly.repository property as a result (but that may be up for debate).

This will add the following entries to the list:

[
  {
    "url": "https://registry.khronos.org/OpenGL/specs/es/3.2/GLSL_ES_Specification_3.20.html",
    "seriesComposition": "full",
    "shortname": "ESSL",
    "series": {
      "shortname": "ESSL",
      "currentSpecification": "ESSL",
      "title": "The OpenGL ES® Shading Language, Version 3.20.8",
      "shortTitle": "OpenGL ES® Shading Language",
      "nightlyUrl": "https://registry.khronos.org/OpenGL/specs/es/3.2/GLSL_ES_Specification_3.20.html"
    },
    "shortTitle": "OpenGL ES® Shading Language 3.20",
    "groups": [
      {
        "name": "OpenGL ES Working Group",
        "url": "https://www.khronos.org/opengles/"
      }
    ],
    "organization": "Khronos Group",
    "nightly": {
      "url": "https://registry.khronos.org/OpenGL/specs/es/3.2/GLSL_ES_Specification_3.20.html",
      "status": "Editor's Draft",
      "alternateUrls": [],
      "filename": "GLSL_ES_Specification_3.20.html"
    },
    "title": "The OpenGL ES® Shading Language, Version 3.20.8",
    "source": "spec",
    "categories": [
      "browser"
    ],
    "standing": "good"
  },
  {
    "url": "https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html",
    "seriesComposition": "full",
    "shortname": "glTF",
    "series": {
      "shortname": "glTF",
      "currentSpecification": "glTF",
      "title": "glTF™ 2.0 Specification",
      "shortTitle": "glTF™",
      "nightlyUrl": "https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html"
    },
    "groups": [
      {
        "name": "glTF Working Group",
        "url": "https://www.khronos.org/gltf/"
      }
    ],
    "nightly": {
      "url": "https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html",
      "status": "Editor's Draft",
      "sourcePath": "specification/2.0/Specification.adoc",
      "alternateUrls": [],
      "repository": "https://github.com/KhronosGroup/glTF",
      "filename": "glTF-2.0.html"
    },
    "organization": "Khronos Group",
    "title": "glTF™ 2.0 Specification",
    "source": "spec",
    "shortTitle": "glTF™ 2.0",
    "categories": [
      "browser"
    ],
    "standing": "good"
  }
]

[tidoust]

One more note: glTF is not currently "directly" supported by web browsers, but is somewhat aligned with WebGL/WebGPU, and could be more directly supported when/if the <model> proposal progresses. I chose to leave it in the browser category. That may be up for debate too!

[dontcallmedom]

Suggested change

	}
	},
	"categories": [
	"-browser"
	]

(since it's not implemented in browsers at the moment)