PEP 7: Mention signed overflow explicitly

Author: matthiasgoergens

pep-0007.txt

@@ -35,6 +35,9 @@ C dialect
   <https://en.wikipedia.org/wiki/C11_%28C_standard_revision%29#Optional_features>`_.
   The public C API should be compatible with C++.
 
+* Python versions up to and including 3.11 tacitly allowed signed arithmetic
+  overflow (wrapping around using twos-complement representation) via the `-fwrapv` compiler option.
+
 * Python 3.6 to 3.10 use C89 with several select C99 features:
 
   - Standard integer types in ``<stdint.h>`` and ``<inttypes.h>``. We