cue/format: add test cases for issue 2496

Both supplied by Tony Worm; the first indents too much,
and the second inserts a newline where there was none.

While here, I noticed this indenting bug appears with parentheses
and selectors as well, and I also noticed that we sometimes indent
top-level comments, which seems like a bug as well.

For #2496.

Signed-off-by: Daniel Martí <mvdan@mvdan.cc>
Change-Id: I978f8acf5469e255d026f737c9b39d7098fd30b3
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1196132
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
Reviewed-by: Aram Hăvărneanu <aram@cue.works>

cue/format/testdata/comments.txtar

@@ -329,3 +329,27 @@ foo: [
 
 	// an ellipsis
 }
+-- comment_alone.input --
+// Just one comment on its own.
+-- comment_alone.golden --
+// Just one comment on its own.
+-- comment_field.input --
+// Just one comment on a field. TODO(mvdan): do not indent.
+foo: string
+-- comment_field.golden --
+	// Just one comment on a field. TODO(mvdan): do not indent.
+foo: string
+-- comments_alone.input --
+// Just a few comments
+// on their own.
+-- comments_alone.golden --
+// Just a few comments
+// on their own.
+-- comments_field.input --
+// Just a few comments
+// on a field.
+foo: string
+-- comments_field.golden --
+// Just a few comments
+// on a field.
+foo: string

cue/format/testdata/expressions.txtar

@@ -565,3 +565,50 @@ import "list"
 	s: [string]: [string]: a
 	s: [string]: {s: string}
 }
+-- issue2496.input --
+// TODO(mvdan): we indent the list elements too much.
+machine_type: [
+	if arch == "amd" {"n2-standard-2"},
+	if arch == "arm" {"t2a-standard-2"},
+	"unknown arch",
+][0]
+
+long_field_name: ([
+	"foo"
+])
+
+long_field_name: [
+	"foo"
+].bar
+
+// TODO(mvdan): we insert an empty line between the definitions.
+_foo: {
+	#tool: string
+	#arch: string
+
+	// skip_create_image: true
+}
+-- issue2496.golden --
+		// TODO(mvdan): we indent the list elements too much.
+machine_type: [
+		if arch == "amd" {"n2-standard-2"},
+		if arch == "arm" {"t2a-standard-2"},
+		"unknown arch",
+][0]
+
+long_field_name: ([
+			"foo",
+])
+
+long_field_name: [
+			"foo",
+].bar
+
+// TODO(mvdan): we insert an empty line between the definitions.
+_foo: {
+	#tool: string
+
+	#arch: string
+
+	// skip_create_image: true
+}