Clarify and Correct Errors in Sentence on Line 24 in app.py

This PR addresses and clarifies the ambiguously phrased sentence on line 24, which currently contains two typographical errors. It revises the sentence to enhance readability and accuracy, ensuring that the intended meaning is clearly communicated.

app.py

@@ -21,7 +21,7 @@ To use it, upload your prompt and set the compression target.
 
 You can check our [project page](https://llmlingua.com/)!
 
-We also has a work to compress long context scenories, using less cost but even improve the downstream performance, LongLLMLingua.<br>
+We also have a project aimed at compressing long context scenarios, which reduces costs while still improving downstream performance, LongLLMLingua.<br>
 [LongLLMLingua: Accelerating and Enhancing LLMs in Long Context Scenarios via Prompt Compression](https://arxiv.org/abs/2310.06839) (Under Review).<br>
 
 ## News