docs: add unit specifications (kg and meters) to calculateBMI comments based on review

Author: Samual-Hu

Sprint-2/3-mandatory-implement/1-bmi.js

@@ -13,7 +13,11 @@
 // Given someone's weight in kg and height in metres
 // Then when we call this function with the weight and height
 // It should return their Body Mass Index to 1 decimal place
-
+/**
+ * Calculates the Body Mass Index (BMI).
+ * @param {number} weight - The weight in kilograms (kg).
+ * @param {number} height - The height in meters (m).
+ */
 function calculateBMI(weight, height) {
     // return the BMI of someone based off their weight and height
     let bmi = weight / (height * height);