Add PR number to ChangeLog (#26512)

I forgot to add this in #26499.

Author: aheejin

ChangeLog.md

@@ -22,7 +22,7 @@ See docs/process.md for more on how version tagging works.
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 - `EXPORT_EXCEPTION_HANDLING_HELPERS` is deprecated and setting it will not do
   anything. `getExceptionMessage` is exported anyway when `ASSERTIONS` or
-  `EXCEPTION_STACK_TRACES` is set, which are set by default at `-O0`.
+  `EXCEPTION_STACK_TRACES` is set, which are set by default at `-O0`. (#26499)
 - The deprecated `EMSCRIPTEN` macro is now defined in `emscripten.h` rather than
   on the command line (`__EMSCRIPTEN__`, which is built into LLVM, should be
   used instead). (#26417)