Merge branch '6.4' into 7.1

* 6.4:
  Minor tweaks
  [Runtime] Document registering your own runtime template

Author: javiereguiluz

components/runtime.rst

@@ -97,6 +97,23 @@ Use the ``APP_RUNTIME`` environment variable or by specifying the
         }
     }
 
+If modifying the runtime class isn't enough, you can create your own runtime template:
+
+.. code-block:: json
+
+    {
+        "require": {
+            "...": "..."
+        },
+        "extra": {
+            "runtime": {
+                "autoload_template": "resources/runtime/autoload_runtime.template"
+            }
+        }
+    }
+
+Symfony provides a `runtime template file`_ that you can use to create your own.
+
 Using the Runtime
 -----------------
 
@@ -472,3 +489,4 @@ The end user will now be able to create front controller like::
 .. _Swoole: https://openswoole.com/
 .. _ReactPHP: https://reactphp.org/
 .. _`PSR-15`: https://www.php-fig.org/psr/psr-15/
+.. _`runtime template file`: https://github.com/symfony/symfony/blob/{version}/src/Symfony/Component/Runtime/Internal/autoload_runtime.template