Added docs for the change of behavior of isin (pandas-dev#39064)

Author: omarafifii

pandas/core/series.py

@@ -4599,6 +4599,15 @@ def isin(self, values) -> Series:
         4     True
         5    False
         Name: animal, dtype: bool
+
+        Strings and integers are distinct and are therefore not comparable:
+
+        >>> pd.Series([1]).isin(['1'])
+        0    False
+        dtype: bool
+        >>> pd.Series([1.1]).isin(['1.1'])
+        0    False
+        dtype: bool
         """
         result = algorithms.isin(self._values, values)
         return self._constructor(result, index=self.index).__finalize__(