Removed struct keyword

tests/programs/allocator.q

@@ -24,12 +24,12 @@ main() {
 	assert b.y == 4
 }
 
-struct Allocator {
+Allocator {
 	block *any
 	current int
 }
 
-struct Point {
+Point {
 	x int
 	y int
 }

tests/programs/function-pointer-field.q

@@ -1,6 +1,6 @@
 import sys
 
-struct Struct {
+Struct {
 	func *any
 }
 

tests/programs/struct-lifetime.q

@@ -3,6 +3,6 @@ main() {
 	c.value += 16
 }
 
-struct Counter {
+Counter {
 	value int
 }

tests/programs/struct.q

@@ -1,4 +1,4 @@
-struct Point {
+Point {
 	x int
 	y int
 }