docs: consistent spacing in tutorial html files (#23105) (#24497)

- Removed surrounding spaces in interpolation expressions following the styleguide
- Consistant spacing of two spaces in html

Fixes #23105

PR Close #24497

aio/content/examples/toh-pt2/src/app/heroes/heroes.component.html

@@ -14,7 +14,7 @@
 <div *ngIf="selectedHero">
 
   <!-- #docregion selectedHero-details -->
-  <h2>{{ selectedHero.name | uppercase }} Details</h2>
+  <h2>{{selectedHero.name | uppercase}} Details</h2>
   <div><span>id: </span>{{selectedHero.id}}</div>
   <div>
     <label>name: