cmd/cue/cmd: convert package block comments in cue get go

Pass package comments through writeDoc.

Issue #173

Change-Id: Ib0438ed38012bcb15128d1315b654111285753d9
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/4140
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/cmd/cue/cmd/get_go.go b/cmd/cue/cmd/get_go.go
index 4229fd7..4476983 100644
--- a/cmd/cue/cmd/get_go.go
+++ b/cmd/cue/cmd/get_go.go
@@ -458,9 +458,7 @@
 		fmt.Fprintln(w, "//cue:generate cue get go", args)
 		fmt.Fprintln(w)
 		if f.Doc != nil {
-			for _, c := range f.Doc.List {
-				fmt.Fprintln(w, c.Text)
-			}
+			writeDoc(w, f.Doc)
 		}
 		fmt.Fprintf(w, "package %s\n", p.Name)
 		fmt.Fprintln(w)
diff --git a/cmd/cue/cmd/testdata/code/go/pkg1/file1.go b/cmd/cue/cmd/testdata/code/go/pkg1/file1.go
index 99fd121..d3d110a 100644
--- a/cmd/cue/cmd/testdata/code/go/pkg1/file1.go
+++ b/cmd/cue/cmd/testdata/code/go/pkg1/file1.go
@@ -12,6 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+/*
+  block comment
+*/
 package pkg1
 
 import (
diff --git a/cmd/cue/cmd/testdata/pkg/cuelang.org/go/cmd/cue/cmd/testdata/code/go/pkg1/file1_go_gen.cue b/cmd/cue/cmd/testdata/pkg/cuelang.org/go/cmd/cue/cmd/testdata/code/go/pkg1/file1_go_gen.cue
index 995d56a..a9de907 100644
--- a/cmd/cue/cmd/testdata/pkg/cuelang.org/go/cmd/cue/cmd/testdata/code/go/pkg1/file1_go_gen.cue
+++ b/cmd/cue/cmd/testdata/pkg/cuelang.org/go/cmd/cue/cmd/testdata/code/go/pkg1/file1_go_gen.cue
@@ -2,6 +2,7 @@
 
 //cue:generate cue get go cuelang.org/go/cmd/cue/cmd/testdata/code/go/pkg1
 
+// block comment
 package pkg1
 
 import (