Add another changelog entry. (#13912)

Author: sean-mcmanus

Extension/CHANGELOG.md

@@ -1,8 +1,9 @@
 # C/C++ for Visual Studio Code Changelog
 
-## Version 1.27.4: September 8, 2025
+## Version 1.27.4: September 9, 2025
 ### Bug Fixes
 * Fix crash recovery. [#13838](https://github.com/microsoft/vscode-cpptools/issues/13838)
+* Fix the language server getting stuck by a notification message box after a configuration provider times out. [#13862](https://github.com/microsoft/vscode-cpptools/issues/13862)
 * Fix a case of unintialized memory in cpptools-srv.
 * Fix excessive cpptools messages when scrolling.
 
@@ -49,6 +50,10 @@
 * Fix activation failing if the `c_cpp_properties.json` exists but fails to be opened. [#13829](https://github.com/microsoft/vscode-cpptools/issues/13829)
 * Fix an IntelliSense bug that could cause incorrect string lengths to be reported for string literals in files that use certain file encodings.
 
+## Version 1.26.4: September 9, 2025
+* Update GitHub Copilot APIs. [PR #13877](https://github.com/microsoft/vscode-cpptools/pull/13877)
+  * Thank you for the contribution. [@dbaeumer (Dirk Bäumer)](https://github.com/dbaeumer)
+
 ## Version 1.26.3: June 24, 2025
 ### New Feature
 * Improve the context provided for C++ Copilot suggestions.