Clarify output range of Rng

lib/random.js

@@ -1,6 +1,13 @@
 /**
- * some stuff in this file copy/pasted from
+ * The seedable PRNG functions are taken from this SO question:
  * https://stackoverflow.com/questions/521295/seeding-the-random-number-generator-in-javascript
+ * And specifically this insanely thorough answer:
+ * https://stackoverflow.com/a/47593316/3991555
+ */
+
+/**
+ * @callback Rng
+ * @returns {number} in range [0, 1)
  */
 
 /**
@@ -55,12 +62,6 @@ export function sfc32(a, b, c, d) {
   };
 }
 
-/**
- * @callback Rng
- * @returns {number} in range [0, 1)
- * TODO@v1: not really sure what the range is, could be [0, 1] or (0, 1)
- */
-
 /**
  * @param {string} seed
  * @returns {Rng}