[go] Fix typo: "default GitHub in PRs"

[SimonAlling]

This passage confused me when I was reading this page:

whether to include Go codegen comment to disable Go Lint and collapse by default GitHub in PRs and diffs (Default: false)

I'm not entirely sure, but I think this PR proposes the intended formulation.

I'm not a Java expert, but I'm also wondering why GoClientCodegen.java has said string hardcoded instead of using WITH_GO_CODEGEN_COMMENT_DESC from CodegenConstants.java, but I guess that's a separate issue (if at all one).

PR checklist

• Read the contribution guidelines.
• Run the shell script(s) under ./bin/ (or Windows batch scripts under.\bin\windows) to update Petstore samples related to your fix. This is important, as CI jobs will verify all generator outputs of your HEAD commit, and these must match the expectations made by your contribution. You only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the code or mustache templates for a language ({LANG}) (e.g. php, ruby, python, etc).
• If contributing template-only or documentation-only changes which will change sample output, build the project before.
• File the PR against the correct branch: master, 4.3.x, 5.0.x. Default: master.
• Copy the technical committee to review the pull request if your PR is targeting a particular programming language.

I assume this is what is meant by the last checkbox above: @antihax (2017/11) @bvwells (2017/12) @grokify (2018/07) @kemokemo (2018/09) @bkabrda (2019/07)

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[bkabrda]

LGTM, nice catch!

[wing328]

@SimonAlling thanks for the PR, which has been included in the 4.3.0 release: https://twitter.com/oas_generator/status/1243455743937789952