Add some missing @throws annotations

src/pocketmine/level/format/io/region/RegionLoader.php

@@ -75,6 +75,9 @@ class RegionLoader{
 		$this->filePath = $filePath;
 	}
 
+	/**
+	 * @throws CorruptedRegionException
+	 */
 	public function open() : void{
 		$exists = file_exists($this->filePath);
 		if(!$exists){
@@ -219,6 +222,9 @@ class RegionLoader{
 		}
 	}
 
+	/**
+	 * @throws CorruptedRegionException
+	 */
 	protected function loadLocationTable() : void{
 		fseek($this->filePointer, 0);
 		$this->lastSector = 1;