new var declaration syntax

examples/puzzles/euler_16.zr

@@ -1,18 +1,18 @@
 func main[] : i64
-    let n = []
+    n := []
     array.push(n, 1)
 
     for j in 0..1000
-        let carry = 0
+        carry := 0
         for i in 0..n->size
-            let tmp: i64 = array.nth(n, i) * 2 + carry
+            tmp : i64 = array.nth(n, i) * 2 + carry
             array.set(n, i, tmp % 10)
             carry = tmp / 10
         while carry > 0
             array.push(n, carry % 10)
             carry = carry / 10
     
-    let sum = 0
+    sum := 0
     for i in 0..n->size
         sum = sum + array.nth(n, i)