Remove 'virtually all'

Author: StanFromIreland

peps/pep-0775.rst

@@ -26,7 +26,7 @@ Motivation
 ==========
 
 The zlib library, which powers the :mod:`!zlib` Python module,
-is available on virtually all systems.
+is available on all supported systems except WASI.
 
 Many wheels on PyPI, including the :pypi:`pip` installer, require zlib.
 Users of pip would consider CPython without zlib to be broken,