internal/third_party/yaml: improve yaml positining

- retain more of the original spacing into the conversion
- store original absolute positions

Change-Id: Id1edbefe1050e1f2dcec3ceb2f8877018b0b5876
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/2562
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/internal/third_party/yaml/parserc.go b/internal/third_party/yaml/parserc.go
index 52d8f74..aaf7f26 100644
--- a/internal/third_party/yaml/parserc.go
+++ b/internal/third_party/yaml/parserc.go
@@ -2,8 +2,6 @@
 
 import (
 	"bytes"
-
-	"cuelang.org/go/cue/token"
 )
 
 // The parser implements the following grammar:
@@ -60,9 +58,8 @@
 	parser.tokens_head++
 }
 
-func add_comment(parser *yaml_parser_t, p token.RelPos, m yaml_mark_t, text string) {
+func add_comment(parser *yaml_parser_t, m yaml_mark_t, text string) {
 	parser.comments = append(parser.comments, yaml_comment_t{
-		pos:  p,
 		mark: m,
 		text: text,
 	})