DOC: update ohlc docstring so that it reflects the real use #31919 (#31941)

Author: dequadras

pandas/core/groupby/groupby.py

@@ -1447,7 +1447,7 @@ def last(x):
     @Appender(_common_see_also)
     def ohlc(self) -> DataFrame:
         """
-        Compute sum of values, excluding missing values.
+        Compute open, high, low and close values of a group, excluding missing values.
 
         For multiple groupings, the result index will be a MultiIndex