internal: store Body in Attr type

Change-Id: Ie0bc6d19647a9c940fd43025d6c9a9636792fb2f
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/9187
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Paul Jolly <paul@myitcv.org.uk>
diff --git a/internal/attrs.go b/internal/attrs.go
index 83200ed..4eeeb6e 100644
--- a/internal/attrs.go
+++ b/internal/attrs.go
@@ -27,6 +27,7 @@
 
 // Attr holds positional information for a single Attr.
 type Attr struct {
+	Body   string
 	Fields []keyValue
 	Err    error
 }
@@ -110,6 +111,7 @@
 }
 
 func ParseAttrBody(pos token.Pos, s string) (a Attr) {
+	a.Body = s
 	i := 0
 	for {
 		i += skipSpace(s[i:])