Remove the distutils-sig@python.org email in 'Installing Python Modules' (python#145613)

Author: StanFromIreland

Doc/installing/index.rst

@@ -6,8 +6,6 @@
 Installing Python Modules
 *************************
 
-:Email: distutils-sig@python.org
-
 As a popular open source development project, Python has an active
 supporting community of contributors and users that also make their software
 available for other Python developers to use under open source license terms.