[clang] [Clang][Sema] fix outline member function template with default align crash (PR #78400)

[Qizhi Hu via cfe-commits]

================
@@ -859,6 +859,9 @@ Bug Fixes in This Version
   Fixes (`#78290 <https://github.com/llvm/llvm-project/issues/78290>`_)
 - Fixed assertion failure with deleted overloaded unary operators.
   Fixes (`#78314 <https://github.com/llvm/llvm-project/issues/78314>`_)
+- Fix crash when specialize out-of-line member function with default parameter
----------------
jcsxky wrote:

Yeah, thanks for your guidance of grammar and expression! I have update the note according to you suggestion.

https://github.com/llvm/llvm-project/pull/78400