Fix bugzilla issue 24495 - ImportC: Struct initialization expression fails to initialize field

[ArthaTi]

Makes it possible to use multiple designated initializers for anonymous structs in expressions like {{ .b = 2, .c = 3 }}. This previously worked only if there was one initializer.

This is my first PR. I had some issues setting up the D runtime and I'm getting linker errors in some tests, but I didn't find any relevant documentation. I built with make/make test.

I have doubts in regards to initializers for anonymous structs/unions in general. I'm not sure if this is the correct way to approach the overall issue, but I will leave it for others to consider.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	24495	major	ImportC: Struct initialization expression fails to initialize field

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "stable + dmd#16369"

[thewilsonator]

Thanks, please retitle the commit Fix bugzilla issue 24495: ImportC: Struct initialization expression fails to initialize field

[dkorpel]

Looks like I hit the exact same bug while using tree-sitter-c:
Issue 24277 - ImportC: struct initializer entry gets ignored (pt2)

Thanks for fixing it! I moved the test in with the other C struct tests in this PR: #16370