[clang] [Clang] Correct the order of substituted arguments in CTAD alias guides (PR #123022)

[via cfe-commits]

================
@@ -1086,18 +1067,14 @@ BuildDeductionGuideForTypeAlias(Sema &SemaRef,
   //  2) non-deduced template parameters of f: rebuild a
   //  template argument;
   //
-  // 2) has been built already (when rebuilding the new template
-  // parameters), we now perform 1).
+  // We now perform 1), as case 2) might refer to substituted 1).
----------------
cor3ntin wrote:

How about

```cpp
// The template argument list is formed, in order,  from
   // 1) For the template parameters of the alias, the corresponding deduced template arguments
   // 2) For the non-deduced template parameters of f. the (rebuilt) template arguments corresponding.

// Note: the non-deduced template arguments of `f` might refer to arguments deduced in 1)
```


https://github.com/llvm/llvm-project/pull/123022