[llvm] Add 3 way compare <=> integer intrinsics to Langref (PR #83227)

[via llvm-commits]

================
@@ -14531,6 +14531,63 @@ The arguments (``%a`` and ``%b``) may be of any integer type or a vector with
 integer element type. The argument types must match each other, and the return
 type must match the argument type.
 
+.. _int_scmp:
+
+'``llvm.scmp.*``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+This is an overloaded intrinsic. You can use ``@llvm.scmp`` on any
+integer bit width or any vector of integer elements.
+
+::
+
+      declare i32 @llvm.scmp.i32(i32 %a, i32 %b)
----------------
scottmcm wrote:

This doesn't match `ucmp` below; is it supposed to be
```suggestion
      declare i2 @llvm.scmp.i32(i32 %a, i32 %b)
```

https://github.com/llvm/llvm-project/pull/83227