[#6648] fix indentation

Author: xabbuh

components/process.rst

@@ -308,8 +308,9 @@ Use :method:`Symfony\\Component\\Process\\Process::disableOutput` and
     However, it is possible to pass a callback to the ``start``, ``run`` or ``mustRun``
     methods to handle process output in a streaming fashion.
 
-.. versionadded:: 3.1
-    The ability to pass a callback to these methods when output is disabled was added in Symfony 3.1.
+    .. versionadded:: 3.1
+        The ability to pass a callback to these methods when output is disabled
+        was added in Symfony 3.1.
 
 .. _`Symfony Issue#5759`: https://github.com/symfony/symfony/issues/5759
 .. _`PHP Bug#39992`: https://bugs.php.net/bug.php?id=39992