docs: changelog and readme limitation

CHANGELOG.md

@@ -5,6 +5,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
+## [Unreleased]
+### Added
+* `/translate` endpoint: added `model_type` request parameter and 
+  `model_type_used` response parameter.
+
+
 ## [1.13.0] - 2024-09-13
 ### Added
 * Add supported glossary languages: Danish (`'da'`), Norwegian (bokmål)
@@ -184,6 +190,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 Initial version.
 
 
+[Unreleased]: https://github.com/DeepLcom/deepl-mock/compare/v1.13.0...HEAD
 [1.13.0]: https://github.com/DeepLcom/deepl-mock/compare/v1.12.0...v1.13.0
 [1.12.0]: https://github.com/DeepLcom/deepl-mock/compare/v1.11.0...v1.12.0
 [1.11.0]: https://github.com/DeepLcom/deepl-mock/compare/v1.10.0...v1.11.0

README.md

@@ -119,6 +119,12 @@ This mock server uses simplified calculations to update account usage.
 ### Formality, tag-handling, formatting 
 This mock server does not implement these features, however the API input parameters are validated.
 
+### Model types
+This mock server allows the quality-optimized models for all language pairs,
+unlike the real DeepL API (which supports a subset of language pairs). Note that
+as this mock server does not implement translation, the model type used has no
+impact.
+
 ## Additional checks compared with the DeepL API
 
 ### User-Agent