fix: typo in usage.md (#598)

minor typo fix (tt -> it)

Author: natowi

docs/usage.md

@@ -5,7 +5,7 @@
 - The tool uses Large Language Model (LLMs) to perform various tasks in a QA pipeline.
   So, you need to provide the application with access to the LLMs you want
   to use.
-- You only need to provide at least one. However, tt is recommended that you include all the LLMs
+- You only need to provide at least one. However, it is recommended that you include all the LLMs
   that you have access to, you will be able to switch between them while using the
   application.