Respect line breaks in operator chains and argument lists (#1268)

If an operator chain or method call is multiline, keep those newlines
in the formatted output.

Help preserve code like:

```
foo
  |> (it) -> it + 2
  |> (it) -> it / 2
```

pkl-formatter/src/test/files/FormatterSnippetTests/input/expr-chain-grouping.pkl

@@ -29,3 +29,6 @@ res10 = foo.bar /* some comment */ (5)
 
 res11 = foo.bar /* some comment */.baz(new { foooooooooooooooooooooooooo = 1; baaaaaaaaaaaaaaaaaaaaar = 2 }).buz
 
+res12 = foo.biz
+  .bar((it) -> it + 2)
+  .qux((it) -> it + 1)

pkl-formatter/src/test/files/FormatterSnippetTests/input/line-breaks3.pkl

@@ -0,0 +1,58 @@
+// respect line breaks on:
+// * operator chains
+// * argument lists in method calls
+//
+// only look for line breaks on either side of the operator, or the comma.
+res1 =
+  foo
+    * bar
+    * baz
+
+res2 = foo
+  |> bar + bar
+  |> baz
+
+res3 = foo
+  |> bar
+    + baz
+  |> qux
+
+res4 = foo(
+  (it) -> it + 1,
+  (it) -> it + 2
+)
+
+res5 = foo(
+  1,
+  2, 3, 4
+)
+
+// don't respect newlines right after opening paren and closing paren
+res6 = foo.bar(
+  1, 2, 3
+)
+
+// only respect newlines on either side of a binary operator (we still want to inline `bar(3)` here).
+res7 = foo + bar(
+      3
+    ) + baz
+
+// only the newlines after each "entry" are respected 
+res8 = Map(
+  1, 2,
+  3, 4
+)
+
+res9 = Map(
+  1,
+  2,
+  3, 4
+)
+
+res10 = foo(1
+  ,2
+  ,3)
+
+res11 = foo +
+  bar +
+  baz

pkl-formatter/src/test/files/FormatterSnippetTests/output/expr-chain-grouping.pkl

@@ -63,3 +63,8 @@ res11 =
   foo.bar /* some comment */
     .baz(new { foooooooooooooooooooooooooo = 1; baaaaaaaaaaaaaaaaaaaaar = 2 })
     .buz
+
+res12 =
+  foo.biz
+    .bar((it) -> it + 2)
+    .qux((it) -> it + 1)

pkl-formatter/src/test/files/FormatterSnippetTests/output/line-breaks3.pkl

@@ -0,0 +1,65 @@
+// respect line breaks on:
+// * operator chains
+// * argument lists in method calls
+//
+// only look for line breaks on either side of the operator, or the comma.
+res1 =
+  foo
+    * bar
+    * baz
+
+res2 =
+  foo
+    |> bar + bar
+    |> baz
+
+res3 =
+  foo
+    |> bar
+      + baz
+    |> qux
+
+res4 =
+  foo(
+    (it) -> it + 1,
+    (it) -> it + 2,
+  )
+
+res5 =
+  foo(
+    1,
+    2,
+    3,
+    4,
+  )
+
+// don't respect newlines right after opening paren and closing paren
+res6 = foo.bar(1, 2, 3)
+
+// only respect newlines on either side of a binary operator (we still want to inline `bar(3)` here).
+res7 = foo + bar(3) + baz
+
+// only the newlines after each "entry" are respected 
+res8 =
+  Map(
+    1, 2,
+    3, 4,
+  )
+
+res9 =
+  Map(
+    1, 2,
+    3, 4,
+  )
+
+res10 =
+  foo(
+    1,
+    2,
+    3,
+  )
+
+res11 =
+  foo
+    + bar
+    + baz