CLN: simplify Float64Index.__contains__ (#30899)

Author: jbrockmendel

pandas/core/indexes/numeric.py

@@ -477,20 +477,7 @@ def __contains__(self, other) -> bool:
         if super().__contains__(other):
             return True
 
-        try:
-            # if other is a sequence this throws a ValueError
-            return np.isnan(other) and self.hasnans
-        except ValueError:
-            try:
-                return len(other) <= 1 and other.item() in self
-            except AttributeError:
-                return len(other) <= 1 and other in self
-            except TypeError:
-                pass
-        except TypeError:
-            pass
-
-        return False
+        return is_float(other) and np.isnan(other) and self.hasnans
 
     @Appender(_index_shared_docs["get_loc"])
     def get_loc(self, key, method=None, tolerance=None):