Support extracting code when initializing test data without field name

[meoconbatu]

This commit only supports anonymous struct type.
To fully support for named struct type requires a lot of changes in the source code.

Fixes #78

[github-actions]

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[coveralls]

Pull Request Test Coverage Report for Build 5382124734

• 20 of 22 (90.91%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.9%) to 65.835%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
testrunner/ast.go	20	22	90.91%

Files with Coverage Reduction	New Missed Lines	%
testrunner/ast.go	1	75.93%

Totals
Change from base Build 4500252823:	0.9%
Covered Lines:	422
Relevant Lines:	641

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💛 - Coveralls

[junedev]

Good catch regarding the missing field names! I did not notice this was the issue why it was not working as expected.
Thanks for the fix. We need to wait for for someone from Exercism staff to approve before it can be merged.

(I did a tiny update to the test data so the test case actually demonstrates that the extraction of one of the cases works as expected now.)