feat: Append individual property to property list

Author: joshbruce

src/Implementations/Properties.php

@@ -14,17 +14,22 @@ trait Properties
     /**
      * @return static $properties [description]
      */
-    public function props(string ...$properties)
+    public function props(string ...$properties): static
     {
         $this->properties = $properties;
         return $this;
     }
 
+    public function prop(string $prop): static
+    {
+        $this->properties[] = $prop;
+        return $this;
+    }
+
     protected function propertiesString(): string
     {
         if (count($this->properties()) === 0) {
             return '';
-
         }
 
         $b = [];

tests/ElementBaselineTest.php

@@ -39,10 +39,20 @@ public function element_can_omit_end_tag(): void
      */
     public function element_can_have_properties(): void
     {
+        // basic
         $this->assertEquals(
             Element::create('root')->props('id 6', 'property hello')->build(),
             '<root id="6" property="hello"></root>'
         );
+
+        // add
+        $this->assertEquals(
+            Element::create('root')
+                ->props('id 6', 'property hello')
+                ->prop('class something')
+                ->build(),
+            '<root id="6" property="hello" class="something"></root>'
+        );
     }
 
     /**