feat(coverage): add statements to lcov reports

[kayagokalp]

Motivation

To improve lcov coverage reports, by adding DA for statements.

closes #6968

Solution

I did a little bit of digging for this one, my first guess was an error with the visitor implementation but it was not the case, it looks like statements are omitted while generating lcov reports. I am not sure about the reason but there is comment that says statement's are not compatible with lcov. I am not very familiar with lcov so not sure about the next statement but, I feel like adding DA to lcov report for statements should work.

foundry/crates/forge/src/coverage.rs

Lines 119 to 120 in e897bd6

	// Statements are not in the LCOV format
	CoverageItemKind::Statement => (),

By changing it to emit DA values I obtained following coverage report for the project reported:

[kayagokalp]

More discussion can be found in the issue tracker #6968.

[mattsse]

not too familiar with this, but this does lgtm

ptal @onbjerg