updated the index.md

docs/en/docs/index.md

@@ -46,7 +46,7 @@ The key features are:
 * **Robust**: Get production-ready code. With automatic interactive documentation.
 * **Standards-based**: Based on (and fully compatible with) the open standards for APIs: <a href="https://github.com/OAI/OpenAPI-Specification" class="external-link" target="_blank">OpenAPI</a> (previously known as Swagger) and <a href="https://json-schema.org/" class="external-link" target="_blank">JSON Schema</a>.
 
-<small>* estimation based on tests on an internal development team, building production applications.</small>
+<small>* estimation based on tests conducted by an internal development team, building production applications.</small>
 
 ## Sponsors { #sponsors }