A variant of do_not_remove_field, but with line 1 not embedded.
-- in.cue --
[_]: x: "hello"
a: x: "hello"
-- out/trim-v3 --
== in.cue
[_]: x: "hello"
a: _
-- diff/-out/trim-v3<==>+out/trim --
diff old new
--- old
+++ new
@@ -1,3 +1,3 @@
 == in.cue
 [_]: x: "hello"
-a: {}
+a: _
-- out/trim-v3-noshare --
== in.cue
[_]: x: "hello"
a: _
-- diff/-out/trim-v3-noshare<==>+out/trim --
diff old new
--- old
+++ new
@@ -1,3 +1,3 @@
 == in.cue
 [_]: x: "hello"
-a: {}
+a: _
-- out/trim --
== in.cue
[_]: x: "hello"
a: {}
