new var declaration syntax

examples/puzzles/euler_21.zr

@@ -1,9 +1,9 @@
 func divisors_sum[n: i64] : i64
-    let k = n
-    let sum = 1
+    k := n
+    sum := 1
 
     for i in 2..k+1
-        let p = 1
+        p := 1
         while k % i == 0
             p = p * i
             k = k / i
@@ -11,10 +11,10 @@ func divisors_sum[n: i64] : i64
     return sum - n
 
 func main[] : i64
-    let sum = 0
+    sum := 0
 
     for i in 2..10000
-        let d = divisors_sum(i)
+        d := divisors_sum(i)
         if i < d && i == divisors_sum(d)
             sum = sum + i + d