refactor: remove obsolete // +build tag

[geogrego]

Describe your changes and provide context

From Go 1.17, the preferred syntax for build constraints is //go:build, which replaces the old // +build form. The old style is now considered deprecated but still supported for backward compatibility.

This change removes the obsolete // +build xxx line, keeping only the modern //go:build xxx directive.

More info: https://github.com/golang/go/issues/41184 and https://go.dev/doc/go1.17#build-lines

Design Doc / Proposal： https://go.dev/design/draft-gobuild

Testing performed to validate your change