x86/resctrl: Add 'resctrl' to the title of the resctrl documentation

The resctrl documentation is titled "User Interface for Resource Control
feature".

Once the documentation follows the code in a move to the filesystem, this
appears in the list of filesystems, but doesn't contain the name of the
filesystem, making it hard to find.

Add 'resctrl' to the title.

Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/20250515165855.31452-15-james.morse@arm.com

Author: James Morse

Documentation/arch/x86/resctrl.rst

@@ -1,9 +1,9 @@
 .. SPDX-License-Identifier: GPL-2.0
 .. include:: <isonum.txt>
 
-===========================================
-User Interface for Resource Control feature
-===========================================
+=====================================================
+User Interface for Resource Control feature (resctrl)
+=====================================================
 
 :Copyright: |copy| 2016 Intel Corporation
 :Authors: - Fenghua Yu <fenghua.yu@intel.com>