internal/core/export: extract docs from nested Vertex values

Change-Id: I8649b2306846b608df09da9c4e2994f1f27437e3
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/8101
Reviewed-by: CUE cueckoo <[email protected]>
Reviewed-by: Marcel van Lohuizen <[email protected]>

Author: mpvl

internal/core/export/extract.go

@@ -37,6 +37,10 @@ func extractDocs(v *adt.Vertex, a []adt.Conjunct) (docs []*ast.CommentGroup) {
 
 	// Collect docs directly related to this Vertex.
 	for _, x := range a {
+		if v, ok := x.Expr().(*adt.Vertex); ok {
+			docs = append(docs, extractDocs(v, v.Conjuncts)...)
+			continue
+		}
 		f, ok := x.Source().(*ast.Field)
 		if !ok || hasShorthandValue(f) {
 			continue