[clang] Ofast deprecation clarifications (PR #101005)

[Vlad Serebrennikov via cfe-commits]

================
@@ -429,8 +429,12 @@ Code Generation Options
 
     :option:`-Ofast` Enables all the optimizations from :option:`-O3` along
     with other aggressive optimizations that may violate strict compliance with
-    language standards. This is deprecated in favor of :option:`-O3`
-    in combination with :option:`-ffast-math`.
+    language standards. This is deprecated in Clang 19 and a warning is emitted
+    that :option:`-O3` in combination with :option:`-ffast-math` should be used
+    instead if the request for non-standard math behavior is intended.  There
----------------
Endilll wrote:

```suggestion
    instead if the request for non-standard math behavior is intended. There
```

https://github.com/llvm/llvm-project/pull/101005