snippet/go.json: added a snippet to return error from if error block

[Shahriar-Sazid]

I have added a snippet to return or do something if error is not nil from a if error block. For example,

if err := validation.validate(req); err != nil {
    return nil, err
}

[gopherbot]

This PR (HEAD: 0cc44a4) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/vscode-go/+/432036 to see it.

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[gopherbot]

Message from Jamal Carvalho:

Patch Set 1:

(1 comment)

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