Issue #10145: the float.is_integer method was undocumented.

Doc/library/stdtypes.rst

@@ -535,6 +535,16 @@ The float type has some additional methods.
    :exc:`OverflowError` on infinities and a :exc:`ValueError` on
    NaNs.
 
+.. method:: float.is_integer()
+
+   Return ``True`` if the float instance is finite with integral
+   value, and ``False`` otherwise::
+
+      >>> (-2.0).is_integer()
+      True
+      >>> (3.2).is_integer()
+      False
+
 Two methods support conversion to
 and from hexadecimal strings.  Since Python's floats are stored
 internally as binary numbers, converting a float to or from a