Updated return type description for evaluate function (#1579)

The evaluate function doc-string is still showing the old Result object
as its return type. Updated it to the EvaluationResult object

Author: taihim

src/ragas/evaluation.py

@@ -113,9 +113,9 @@ def evaluate(
 
     Returns
     -------
-    Result
-        Result object containing the scores of each metric. You can use this do analysis
-        later.
+    EvaluationResult
+        EvaluationResult object containing the scores of each metric. 
+        You can use this do analysis later.
 
     Raises
     ------