feat(favicon): add plugin to expose favicon from icon.png (#1942)

* feat(favicon): add plugin to expose favicon from icon.png

* chore(favicon): clean up formatting and remove unnecessary line breaks

quartz/plugins/emitters/favicon.ts

@@ -0,0 +1,16 @@
+import sharp from "sharp"
+import { joinSegments, QUARTZ, FilePath } from "../../util/path"
+import { QuartzEmitterPlugin } from "../types"
+
+export const Favicon: QuartzEmitterPlugin = () => ({
+  name: "Favicon",
+  async *emit({ argv }) {
+    const iconPath = joinSegments(QUARTZ, "static", "icon.png")
+    const dest = joinSegments(argv.output, "favicon.ico") as FilePath
+
+    await sharp(iconPath).resize(48, 48).toFormat("png").toFile(dest)
+
+    yield dest
+  },
+  async *partialEmit() {},
+})