Add format clock edge cases exercise

Author: illicitonion

format-clock-edge-cases/README.md

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+In your prep, you looked this `formatAs12HourClock` function:
+
+```js
+function formatAs12HourClock(time) {
+
+  const hours = Number(time.slice(0, 2));
+
+  if (hours > 12) {
+    return `${hours - 12}:00 pm`;
+  }
+  return `${time} am`;
+}
+```
+
+It still has bugs. Think of as many edge-cases as you can with this code. Write tests for all of them, and fix this code so that it works correctly for all valid inputs. You don't need to worry about invalid inputs (e.g. `"25:00"`).

format-clock-edge-cases/timeConverter.js

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+function formatAs12HourClock(time) {
+
+  const hours = Number(time.slice(0, 2));
+
+  if (hours > 12) {
+    return `${hours - 12}:00 pm`;
+  }
+  return `${time} am`;
+}
+
+export {formatAs12HourClock};

format-clock-edge-cases/timeConverter.test.js

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+import {formatAs12HourClock} from "./timeConverter.js";
+import assert from "node:assert";
+import test from "node:test";
+
+test("correctly convert time after 12:00", function(){
+    assert.equal(formatAs12HourClock("23:00"), "11:00 pm");
+});
+
+test("can correctly convert morning time", function() {
+    assert.equal(formatAs12HourClock("08:00"), "08:00 am");
+});