docs: update docs-style-guide (#36281)

This commit updates the documentation style guide
so that it is in line with current standards, those
of Google as well as those within the Angular docs.

PR Close #36281

aio/content/examples/docs-style-guide/src/app/not-great.component.ts

@@ -0,0 +1,13 @@
+import { Component } from '@angular/core';
+
+@Component({
+  selector: 'app-not-great',
+})
+// #docregion not-great
+export class NotGreatComponent {
+
+  buggyFunction() {
+    // things could be better here...
+  }
+}
+// #enddocregion not-great