[8.x] Added $attributes->class() to Blade docs

Feature PR: laravel/framework#36131

blade.md

@@ -906,6 +906,33 @@ The final, rendered HTML of the component will appear like the following:
 </div>
 ```
 
+<a name="conditionally-merge-classes"></a>
+#### Conditionally Merge Classes
+
+You may conditionally merge a set of classes with the `class` method by passing an array of classes.
+
+    <div {{ $attributes->class(['p-4', 'mb-4']) }}>
+        {{ $message }}
+    </div>
+
+Sometimes you may wish to merge classes by specifying conditions. You can accomplish this by passing an array of classes where the array value evaluates to `true`.
+
+    <div {{ $attributes->class(['p-4', 'bg-red' => $hasError]) }}>
+        {{ $message }}
+    </div>
+
+If you need to pass other attributes, you can chain the `merge` method.
+
+    <button {{ $attributes->class(['p-4'])->merge(['type' => 'button']) }}>
+        {{ $slot }}
+    </button>
+
+For convenience, the `class` method accepts a string as well.
+
+    <div {{ $attributes->class('p-4') }}>
+        {{ $message }}
+    </div>
+
 <a name="non-class-attribute-merging"></a>
 #### Non-Class Attribute Merging