PEP 670: fix a grammar mistake

pep-0670.rst

@@ -32,7 +32,7 @@ Rationale
 The use of macros may have unintended adverse effects that are hard to
 avoid, even for experienced C developers. Some issues have been known
 for years, while others have been discovered recently in Python.
-Working around macro pitfalls makes the macro coder harder to read and
+Working around macro pitfalls makes the macro code harder to read and
 to maintain.
 
 Converting macros to functions has multiple advantages: