Update declaration of the binarySearch function.

[paulnice]

Problem: Previous declaration wasn't compatible with the tests:

test_binary_search.zig:10:20: error: expected 2 argument(s), found 3
    const actual = binarySearch(i4, 6, &array);
                   ^~~~~~~~~~~~
binary_search.zig:3:5: note: function declared here

Solution: declare the function properly.

Testing: with existing test cases

[github-actions]

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[ee7]

Thanks for the PR.

It's intended that the user has to modify the function signature in the solution stub sometimes - I think there's some value in the user adding this themselves. That's why the modified file has the comment:

zig/exercises/practice/binary-search/binary_search.zig

Lines 1 to 3 in fe9bca6

	// Take a look at the tests, you might have to change the function arguments
	pub fn binarySearch(target: usize, items: []const usize) ?usize {

But I'm sure this could be a bit awkward or unexpected, since the user gets used to starting out with correct function signatures in previous exercises. In general the track doesn't work like Ziglings, which emphasises fixing broken programs. But I recall that at least the later linked-list exercise stub also doesn't provide complete function signatures.

Rather than merging this PR, I'm leaning towards trying to clarify further (in this file, and/or adding a note to this exercise's docs) that the function signature here needs to be completed. Does that sound good to you? Happy to hear your thoughts on that, or on anything else with the track. Thanks.

[paulnice]

It is up to you.. I don't read full task explanation usually. Too much text to my taste.
Now I know it's ok to have wrong function declaration. I think it is better to show this case earlier, to get least surprise from the user. Probably in the first, second exercise. It would be like showing game rules for a newbie.