Rename Route::parseExtensions() to Route::extensions()

Having the same method names across RouteBuilder, and Route make it
easier to remember which method is correct. Additionally, the
RouteCollection will also be getting an extensions method.

src/Routing/Route/Route.php

@@ -111,13 +111,16 @@ public function __construct($template, $defaults = [], array $options = []) {
 	}
 
 /**
- * Sets the supported extensions for this route.
+ * Get/Set the supported extensions for this route.
  *
- * @param array $extensions The extensions to set.
- * @return void
+ * @param null|array $extensions The extensions to set. Use null to get.
+ * @return array|void The extensions or null.
  */
-	public function parseExtensions(array $extensions) {
-		$this->_extensions = $extensions;
+	public function extensions($extensions = null) {
+		if ($extensions === null) {
+			return $this->_extensions;
+		}
+		$this->_extensions = (array)$extensions;
 	}
 
 /**

tests/TestCase/Routing/Route/RouteTest.php

@@ -105,7 +105,7 @@ public function testRouteParsingWithExtensions() {
 		$result = $route->parse('/posts/index.pdf');
 		$this->assertFalse(isset($result['_ext']));
 
-		$route->parseExtensions(array('pdf', 'json', 'xml'));
+		$route->extensions(array('pdf', 'json', 'xml'));
 		$result = $route->parse('/posts/index.pdf');
 		$this->assertEquals('pdf', $result['_ext']);