#20135: move FAQ about mutable default arguments to the programming FAQs page.
Issue #21923: Prevent AttributeError in distutils.sysconfig.customize_compiler
due to possible uninitialized _config_vars.  Original patch by Alex Gaynor.
Issue #21714: Disallow the construction of invalid paths using Path.with_name().  Original patch by Antony Lee.
Issue #20639: calling Path.with_suffix('') allows removing the suffix again.
Patch by July Tikhonov.