docs(operators): add documentation for last

src/operator-docs/filtering/last.ts

@@ -1,6 +1,47 @@
 import { OperatorDoc } from '../operator.model';
 
 export const last: OperatorDoc = {
-  'name': 'last',
-  'operatorType': 'filtering'
+  name: 'last',
+  operatorType: 'filtering',
+  signature: 'public last(predicate: function): Observable',
+  useInteractiveMarbles: true,
+  parameters: [
+    {
+      name: 'predicate',
+      type: 'function',
+      attribute: '',
+      description: 'The condition any source emitted item has to satisfy.'
+    }
+  ],
+  marbleUrl: 'http://reactivex.io/rxjs/img/last.png',
+  shortDescription: {
+    description: `Emits only the last value emitted by the source Observable.`
+  },
+  walkthrough: {
+    description: `<p>
+      <span class="markdown-code">last</span> Returns an Observable that emits only the last item emitted by the source Observable.
+    </p>
+    <p>
+       It optionally takes a predicate function as a parameter,
+       in which case, rather than emitting the last item from the source Observable,
+       the resulting Observable will emit the last item from the source Observable that satisfies the predicate.
+    </p>`
+  },
+  examples: [
+    {
+      name: 'Get the last number that is divisible by 3',
+      code: `
+      const range = Rx.Observable.range(1, 10);
+      const last = range.last(x => x % 3 === 0);
+      last.subscribe(x => console.log(x));
+      // Logs below values
+      // 9
+      `,
+      externalLink: {
+        platform: 'JSBin',
+        url: 'http://jsbin.com/reqacoselu/embed?html,js,console'
+      }
+    }
+  ],
+  relatedOperators: ['takeLast', 'first']
 };