feat: make sqrt constants

- performance: saves a few bytes when tested with terser
- actually fix rollup annotation warning

simplex-noise.ts

@@ -30,12 +30,14 @@ Better rank ordering method by Stefan Gustavson in 2012.
 
 // these __PURE__ comments help uglifyjs with dead code removal
 //
-const F2 = 0.5 * (/*#__PURE__*/Math.sqrt(3.0) - 1.0);
-const G2 = (3.0 - /*#__PURE__*/Math.sqrt(3.0)) / 6.0;
+const SQRT3 = /*#__PURE__*/ Math.sqrt(3.0);
+const SQRT5 = /*#__PURE__*/ Math.sqrt(5.0);
+const F2 = 0.5 * (SQRT3 - 1.0);
+const G2 = (3.0 - SQRT3) / 6.0;
 const F3 = 1.0 / 3.0;
 const G3 = 1.0 / 6.0;
-const F4 = (/*#__PURE__*/Math.sqrt(5.0) - 1.0) / 4.0;
-const G4 = (5.0 - /*#__PURE__*/Math.sqrt(5.0)) / 20.0;
+const F4 = (SQRT5 - 1.0) / 4.0;
+const G4 = (5.0 - SQRT5) / 20.0;
 
 // I'm really not sure why this | 0 (basically a coercion to int)
 // is making this faster but I get ~5 million ops/sec more on the