Since a fenced code block (three backticks) is already used, there's no need to indent code blocks. Either a fenced code block or an indent alone is enough.
Also use tabs instead of spaces in Go code to make it gofmt-compatible, and use Go syntax highlighting for Go code blocks.
Unlike 1e1ffecf4f148c30fb214feeb491c7de5fe54e56, only use Go syntax highlighting for complete Go code block, since GitHub renders it poorly for partial Go code.
