vello_hybrid: Add more descriptive message if WebGl2 context creation fails

sparse_strips/vello_hybrid/src/render/webgl/mod.rs

diff --git a/sparse_strips/vello_hybrid/src/render/webgl/mod.rs b/sparse_strips/vello_hybrid/src/render/webgl/mod.rs
index 484cd21..04e4bf5 100644
--- a/sparse_strips/vello_hybrid/src/render/webgl/mod.rs
+++ b/sparse_strips/vello_hybrid/src/render/webgl/mod.rs
@@ -238,7 +238,7 @@
         let gl = canvas
             .get_context_with_context_options("webgl2", &context_options)
             .expect("WebGL2 context to be available")
-            .unwrap()
+            .expect("WebGL2 context creation failed: This is possibly due to `failIfMajorPerformanceCaveat` being triggered")
             .dyn_into::<WebGl2RenderingContext>()
             .expect("Context to be a WebGL2 context");