replace leading _ for private symbols with keyword hide

examples/programs/arraylist/main.bro

@@ -2,25 +2,25 @@ arraylist :: import "@std/arraylist"
 mem :: import "@std/mem"
 std :: import "@std"
 
-_fail_alloc func(_ ?*mut anyopaque, _ usize, _ usize) ?*mut u8 {
+hide fail_alloc func(_ ?*mut anyopaque, _ usize, _ usize) ?*mut u8 {
 	return none
 }
 
-_fail_realloc func(_ ?*mut anyopaque, _ ?*mut u8, _ usize, _ usize, _ usize) ?*mut u8 {
+hide fail_realloc func(_ ?*mut anyopaque, _ ?*mut u8, _ usize, _ usize, _ usize) ?*mut u8 {
 	return none
 }
 
-_fail_free func(_ ?*mut anyopaque, _ ?*mut u8, _ usize, _ usize) void {}
+hide fail_free func(_ ?*mut anyopaque, _ ?*mut u8, _ usize, _ usize) void {}
 
-_fail_vtable mem.AllocatorVTable :: mem.AllocatorVTable {
-	alloc = _fail_alloc,
-	realloc = _fail_realloc,
-	free = _fail_free,
+hide fail_vtable mem.AllocatorVTable :: mem.AllocatorVTable {
+	alloc = fail_alloc,
+	realloc = fail_realloc,
+	free = fail_free,
 }
 
-_fail_allocator mem.Allocator :: mem.Allocator {
+hide fail_allocator mem.Allocator :: mem.Allocator {
 	context = none,
-	vtable = &_fail_vtable,
+	vtable = &fail_vtable,
 }
 
 run func() i32 ! mem.AllocError {
@@ -59,7 +59,7 @@ run func() i32 ! mem.AllocError {
 	}
 	if (empty_values.items.len != 1) return 8
 
-	failed arraylist.ArrayList(i32) = arraylist.init(i32, _fail_allocator)
+	failed arraylist.ArrayList(i32) = arraylist.init(i32, fail_allocator)
 	failed_as_expected bool = false
 	arraylist.append(&failed, 1) catch |_| {
 		failed_as_expected = true