Fix typos.

pep-0557.rst

@@ -31,7 +31,7 @@ variables with type annotations as defined in PEP 526, "Syntax for
 Variable Annotations".  In this document, such variables are called
 fields.  Using these fields, the decorator adds generated method
 definitions to the class to support instance initialization, a repr,
-comparisons methods, and optionally other methods as described in the
+comparison methods, and optionally other methods as described in the
 Specification_ section.  Such a class is called a Data Class, but
 there's really nothing special about the class: the decorator adds
 generated methods to the class and returns the same class it was
@@ -83,7 +83,7 @@ to the InventoryItem class::
           return (self.name, self.unit_price, self.quantity_on_hand) >= (other.name, other.unit_price, other.quantity_on_hand)
       return NotImplemented
 
-Data Classes saves you from writing and maintaining these methods.
+Data Classes save you from writing and maintaining these methods.
 
 Rationale
 =========