[Editorial] Fix a missing parenthesis (gpuweb#4712)

This CL add a missing parenthesis in note text.

spec/index.bs

@@ -1256,7 +1256,7 @@ of objects on the device or potentially corrupt internal implementation/driver s
 the device **should** be lost to prevent these changes from being observable.
 
 Note:
-For all device losses not initiated by the application (via {{GPUDevice/destroy()}},
+For all device losses not initiated by the application (via {{GPUDevice/destroy()}}),
 user agents should consider issuing developer-visible warnings *unconditionally*,
 even if the {{GPUDevice/lost}} promise is handled.
 These scenarios should be rare, and the signal is vital to developers because most of the WebGPU