shank() - array - duplicates Array.prototype.splice() except returns a new array instead of mutating in-place

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+### shank
+
+Has the same functionality as [`Array.prototype.splice()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice), but returning a new array instead of mutating the original array.
+
+Use `Array.slice()` and `Array.concat()` to get a new array with the new contents after removing existing elements and/or adding new elements.
+Omit the second argument, `index`, to start at `0`.
+Omit the third argument, `delCount`, to remove `0` elements.
+Omit the fourth argument, `elements`, in order to not add any new elements.
+
+```js
+const shank = (arr, index = 0, delCount = 0, ...elements) => 
+  arr.slice(0, index)
+     .concat(elements)
+     .concat(arr.slice(index + delCount));
+```
+
+```js
+const names = ['alpha', 'bravo', 'charlie'];
+const namesAndDelta = shank(names, 1, 0, 'delta'); // [ 'alpha', 'delta', 'bravo', 'charlie' ]
+const namesNoBravo = shank(names, 1, 1); // [ 'alpha', 'charlie' ]
+console.log(names); // ['alpha', 'bravo', 'charlie']
+```
+