add some comments

app/UI/VmCreate/Validators/DiskSizeValidator.php

@@ -35,22 +35,24 @@ class DiskSizeValidator extends BaseValidator
             $additionalSize = (int) $additionalData->get('formData')[$this->additionalField];
         }
         $diskResource = $resurceManager->disk();
+        # find available space in VDC
         $diskResource->setTotal($diskResource->getTotal()-$additionalSize);
         if ($this->isWhmcsConfigOption(ConfigurableOption::STORAGE)) {
             $this->maxValue = $this->getWhmcsConfigOption(ConfigurableOption::STORAGE) - $diskResource->getUsed();
         } else {
             $this->maxValue = $diskResource->free();
         }
-
+        # reduce available space to server limits
         if ($this->maxValue > $diskResource->getMax()) {
             $this->maxValue = $diskResource->getMax();
         }
-
         $this->minValue = $diskResource->getMin();
+        # reject floating point
         if(preg_match("/\./", $data)){
             $this->addValidationError('PleaseProvideANumericValueBetween', false, ['minValue' => $this->minValue, 'maxValue' => $this->maxValue]);
             return false;
         }
+        # accept if no limits
         if (is_numeric($data) && $this->minValue === 0 && $this->maxValue === 0)
         {
             return true;