gmallard/go-samp: rangecopy/rangecopy.go; 4 LoC

Found a possible issue in [gmallard/go-samp](https://www.github.com/gmallard/go-samp) at [rangecopy/rangecopy.go](https://github.com/gmallard/go-samp/blob/cc56c4e1cc41f91fc3c99e5a06c735e097339c10/rangecopy/rangecopy.go#L63-L66)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first issue it finds, so please do not limit your consideration to the contents of the below message.

> reference to sf is reassigned at line 64

[Click here to see the code in its original context.](https://github.com/gmallard/go-samp/blob/cc56c4e1cc41f91fc3c99e5a06c735e097339c10/rangecopy/rangecopy.go#L63-L66)

Click here to show the 4 line(s) of Go which triggered the analyzer.

```go
for _, sf := range someFoos {
z := &sf
z.a = z.a + 1
}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: cc56c4e1cc41f91fc3c99e5a06c735e097339c10

Review rangecopy/rangecopy.go at lines 63-66 and the analyzer message about the reassigned range-loop reference. Decide whether the finding is a Bug, Mitigated, or Desirable Behavior, then record the classification with the requested reaction.

Written by the indexing model from the issue text.