Go "exported loop pointer" example is outdated

[josharian]

Go finally fixed the language to make https://github.com/getgrit/stdlib/blob/main/.grit/patterns/go/exported_loop_pointer.md unnecessary--see https://go.dev/blog/loopvar-preview. So assuming go.mod is >= 1.22, probably the right fix is to find and remove all x := x instances. :)

Not sure whether GritQL supports conditioning on the go.mod version.

[morgante]

We don't support conditioning on go.mod versions currently. Since the rule isn't applied automatically we could probably just make a (different) parallel rule to remove the x := x instances.