CodeController.foldImports does not fold a multiline import in Go

[alexeyinkin]

Reproducible with MinimalWordCount example in Playground. In short:

// license
// license
package main

import (
  "context"
  "fmt"
  "regexp"

  "github.com/apache/beam/sdks/v2/go/pkg/beam"
  "github.com/apache/beam/sdks/v2/go/pkg/beam/io/textio"
  "github.com/apache/beam/sdks/v2/go/pkg/beam/runners/direct"
  "github.com/apache/beam/sdks/v2/go/pkg/beam/transforms/stats"

  _ "github.com/apache/beam/sdks/v2/go/pkg/beam/io/filesystem/gcs"
  _ "github.com/apache/beam/sdks/v2/go/pkg/beam/io/filesystem/local"
)

[alexeyinkin]

The block is recognized as union because the imports block is joined with the parentheses block. Things to try:

1. If joining imports block with anything, the joined type must be imports.
2. Check how this works without package line. Does import on its own create a block? If not, then the result will just be a parentheses block. Need a workaround for this.