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-pt1/src/app/heroes/heroes.component.1.html

@@ -3,7 +3,7 @@
 <!-- #enddocregion show-hero-1 -->
 
 <!-- #docregion show-hero-2 -->
-<h2>{{ hero.name }} Details</h2>
+<h2>{{hero.name}} Details</h2>
 <div><span>id: </span>{{hero.id}}</div>
 <div><span>name: </span>{{hero.name}}</div>
 <!-- #enddocregion show-hero-2 -->

aio/content/examples/toh-pt1/src/app/heroes/heroes.component.html

@@ -1,6 +1,6 @@
 <!-- #docregion -->
 <!-- #docregion pipe -->
-<h2>{{ hero.name | uppercase }} Details</h2>
+<h2>{{hero.name | uppercase}} Details</h2>
 <!-- #enddocregion pipe -->
 <div><span>id: </span>{{hero.id}}</div>
 <div>

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:

aio/content/examples/toh-pt3/src/app/hero-detail/hero-detail.component.html

@@ -1,6 +1,6 @@
 <div *ngIf="hero">
 
-  <h2>{{ hero.name | uppercase }} Details</h2>
+  <h2>{{hero.name | uppercase}} Details</h2>
   <div><span>id: </span>{{hero.id}}</div>
   <div>
     <label>name:

aio/content/examples/toh-pt4/src/app/hero-detail/hero-detail.component.html

@@ -1,5 +1,5 @@
 <div *ngIf="hero">
-  <h2>{{ hero.name | uppercase }} Details</h2>
+  <h2>{{hero.name | uppercase}} Details</h2>
   <div><span>id: </span>{{hero.id}}</div>
   <div>
     <label>name:

aio/content/examples/toh-pt5/src/app/hero-detail/hero-detail.component.html

@@ -1,5 +1,5 @@
 <div *ngIf="hero">
-  <h2>{{ hero.name | uppercase }} Details</h2>
+  <h2>{{hero.name | uppercase}} Details</h2>
   <div><span>id: </span>{{hero.id}}</div>
   <div>
     <label>name:

aio/content/examples/toh-pt6/src/app/hero-detail/hero-detail.component.html

@@ -1,5 +1,5 @@
 <div *ngIf="hero">
-  <h2>{{ hero.name | uppercase }} Details</h2>
+  <h2>{{hero.name | uppercase}} Details</h2>
   <div><span>id: </span>{{hero.id}}</div>
   <div>
     <label>name: