fix changelog formatting

Author: baronfel

CHANGELOG.md

@@ -6,11 +6,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [0.4.17] - 27.07.2023
 
-* Update a type signature on the SignatureInformation structure
+### Added
 
+* Update a type signature on the SignatureInformation structure
 
 ## [0.4.16] - 27.07.2023
 
+### Added
+
 * [Add missing features for LSP Specification 3.17](https://github.com/ionide/LanguageServerProtocol/pull/52) (thanks @tcx4c70!)
 
 ## [0.4.15] - 13.06.2023