Added an icon to the calendar widget in the bar. (#181)

* Added an icon to the calendar widget in the bar.

* Updated themes for calendar icon.

modules/bar/SideEffects.ts

@@ -0,0 +1,15 @@
+import options from "options";
+
+const { showIcon, showTime } = options.bar.clock;
+
+showIcon.connect("changed", () => {
+    if (!showTime.value && !showIcon.value) {
+        showTime.value = true;
+    }
+});
+
+showTime.connect("changed", () => {
+    if (!showTime.value && !showIcon.value) {
+        showIcon.value = true;
+    }
+});