remove useless getMax method from interval

Author: dan-on

src/Interval.php

@@ -77,9 +77,4 @@ public function merge(Interval $otherInterval): Interval
             max($this->getHigh(), $otherInterval->getHigh())
         );
     }
-
-    public function getMax(): Interval
-    {
-        return $this;
-    }
 }

src/Node.php

@@ -125,7 +125,7 @@ public function copyPairFrom(Node $otherNode): void
 
     public function updateMax(): void
     {
-        $this->max = $this->getPair()->getInterval()->getMax();
+        $this->max = $this->getPair()->getInterval();
 
         if ($this->getRight()->max !== null) {
             $this->max = $this->max->merge($this->getRight()->max);