Add a changelog entry. (#13270)

Author: sean-mcmanus

Extension/CHANGELOG.md

@@ -8,6 +8,7 @@
 * Improve/fix the switch header/source feature. [#2635](https://github.com/microsoft/vscode-cpptools/issues/2635)
 
 ### Bug Fixes
+* Fix an IntelliSense crash in `build_sections`. [#12666](https://github.com/microsoft/vscode-cpptools/issues/12666), [#12956](https://github.com/microsoft/vscode-cpptools/issues/12956)
 * Fix a bug in which hundreds of custom configuration requests could be sent on startup before the configuration provider has registered. [#13166](https://github.com/microsoft/vscode-cpptools/issues/13166)
 * Fix handling of the `-framework` compiler argument. [#13204](https://github.com/microsoft/vscode-cpptools/issues/13204)
 * Fix a potential race between didChange and didOpen. [PR #13209](https://github.com/microsoft/vscode-cpptools/pull/13209)