Auto merge of #25545 - szeged:mmatyas__webgl_fns_versions, r=jdm

Add WebGL2 specific version strings

Updated the `VERSION` and `SHADING_LANGUAGE_VERSION` WebGL parameters to report the correct version strings when WebGL2 is in use.

See: https://www.khronos.org/registry/webgl/specs/latest/2.0/#3.7.2

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cc @jdm @zakorgy @imiklos

---
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- [x] There are tests for these changes

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components/script/dom/webgl2renderingcontext.rs

@@ -443,6 +443,16 @@ impl WebGL2RenderingContextMethods for WebGL2RenderingContext {
     /// https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.3
     fn GetParameter(&self, cx: JSContext, parameter: u32) -> JSVal {
         match parameter {
+            constants::VERSION => unsafe {
+                rooted!(in(*cx) let mut rval = UndefinedValue());
+                "WebGL 2.0".to_jsval(*cx, rval.handle_mut());
+                return rval.get();
+            },
+            constants::SHADING_LANGUAGE_VERSION => unsafe {
+                rooted!(in(*cx) let mut rval = UndefinedValue());
+                "WebGL GLSL ES 3.00".to_jsval(*cx, rval.handle_mut());
+                return rval.get();
+            },
             constants::MAX_CLIENT_WAIT_TIMEOUT_WEBGL => {
                 return Int32Value(
                     self.base.limits().max_client_wait_timeout_webgl.as_nanos() as i32