Fix misleading example for 'file-header'

[ghost]

Old example was wrong (braces missing, regex wrong) and therefore misleading

Old example for file-header: "file-header": "true", "Copyright \d{4}"
New example for file-header: "file-header": [true, "Copyright \\d{4}]"

[palantirtech]

Thanks for your interest in palantir/tslint, @christiandreher! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

[ScottSWu]

I think the docs are generated, so the problem is in the original rule source: https://github.com/palantir/tslint/blob/master/src/rules/fileHeaderRule.ts#L14

[ghost]

Oh, I'm sorry, I didn't know that. I will update the PR then asap. Thank you for pointing that out.

[ghost]

I reverted the changes on the docs, resulting in 3 unnecessary commits. You can deny this PR and I'll do a proper one if you want

[adidahiya]

@christiandreher this is fine, we squash + merge on Github anyway.

👍

[ghost]

Nice, thanks for that quick feedback