[DOCS] Remove paragraph about isAvailable

Author: fsuter

Documentation/Developer/Index.rst

@@ -28,10 +28,6 @@ easy task. The first step is to get the proper service object, with the desired
    $registry = GeneralUtility::makeInstance(\Cobweb\Svconnector\Registry\ConnectorRegistry::class);
    $connector = $registry->getServiceForType('sql', $parameters);
 
-An additional step could be to check if the service is indeed available,
-by calling :php:`$connector->isAvailable()`, although - in this particular
-case - the SQL connector service is always available.
-
 The next step is simply to call the appropriate method from the API
 depending on which format you want to have in return. For a PHP array: