Disable modernize-use-designated-initializers.

Given we are not on c++20, and it will be a while before we get there,
this warning is just noise.

Change-Id: I5b711b92a7382c393dc87e9b9bd704c75fbaabc1
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/203894
Reviewed-by: Antonio Maiorano <[email protected]>
Auto-Submit: dan sinclair <[email protected]>
Commit-Queue: Antonio Maiorano <[email protected]>

.clang-tidy

@@ -110,6 +110,7 @@ Checks: "-*,\
           -modernize-use-auto,\
           -modernize-use-bool-literals,\
           -modernize-use-default-member-init,\
+          -modernize-use-designated-initializers,\
           -modernize-use-emplace,\
           -modernize-use-equals-default,\
           -modernize-use-equals-delete,\