Allow arguments before and after block-formatted functions.

test/splitting/function_arguments.stmt

 40 columns                              |
->>> args before and after function forces nesting
+>>> args before and after function do not force nesting
 method(first,() {fn;},third);
 <<<
-method(
-    first,
-    () {
-      fn;
-    },
-    third);
+method(first, () {
+  fn;
+}, third);
 >>> nothing but function args does not nest
 longFunctionName(() {;}, () {;}, () {;});
 <<<
 longFunctionName(() {
   ;
 }, () {
   ;
 }, () {
   ;
 });
@@ skipping 140 matching lines @@
   body;
 }));
 >>> do nest because of nested many-arg method call
 obj.outer(argument, obj.inner(() {body;}));
 <<<
 obj.outer(
     argument,
     obj.inner(() {
       body;
     }));
->>> force named args to split on positional function
+>>> do not force named args to split on positional function
 function(argument, () {;},
     named: argument, another: argument);
 <<<
-function(
-    argument,
-    () {
-      ;
-    },
-    named: argument,
-    another: argument);
+function(argument, () {
+  ;
+}, named: argument, another: argument);
+>>> args before and after functions split independently
+longFunction(argument, argument, argument, argument, argument,
+() {;}, () {;}, argument, argument, argument, argument, argument);
+<<<
+longFunction(argument, argument,
+    argument, argument, argument, () {
+  ;
+}, () {
+  ;
+}, argument, argument, argument,
+    argument, argument);