[clang] [clang] Add reference to documentation of SysVABI (PR #85022)

[via cfe-commits]

https://github.com/ZeppLu created https://github.com/llvm/llvm-project/pull/85022

The documentation has already been there in `AttrDocs.td`, just lacks proper reference

>From 814db124d1f9bba3fe5878b93bc4cad520160005 Mon Sep 17 00:00:00 2001
From: Zepp <luzepu678 at gmail.com>
Date: Wed, 13 Mar 2024 13:25:43 +0800
Subject: [PATCH] [clang] Add reference to documentation of SysVABI

---
 clang/include/clang/Basic/Attr.td | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 63efd85dcd4e58..67d87eca16ede8 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -2934,7 +2934,7 @@ def Suppress : DeclOrStmtAttr {
 def SysVABI : DeclOrTypeAttr {
   let Spellings = [GCC<"sysv_abi">];
 //  let Subjects = [Function, ObjCMethod];
-  let Documentation = [Undocumented];
+  let Documentation = [SysVABIDocs];
 }
 
 def ThisCall : DeclOrTypeAttr {