[clang] [Clang] Accept auto parameters pre-C++20 as an extension (PR #200670)

[Aaron Ballman via cfe-commits]

================
@@ -371,7 +372,7 @@ Modified Compiler Flags
 - The `-mno-outline` flag will now add the `nooutline` IR attribute, so that
   `-mno-outline` and `-moutline` objects can be mixed correctly during LTO.
 
-- Slightly changed hash id generation to get the unique linkage symbols names 
+- Slightly changed hash id generation to get the unique linkage symbols names
----------------
AaronBallman wrote:

A lot of unrelated changes snuck in.

https://github.com/llvm/llvm-project/pull/200670