Trim the out-of-date site.py docstring

Author: warsaw

Lib/site.py

@@ -18,57 +18,25 @@
 it is also checked for site-packages (sys.base_prefix and
 sys.base_exec_prefix will always be the "real" prefixes of the Python
 installation). If "pyvenv.cfg" (a bootstrap configuration file) contains
-the key "include-system-site-packages" is set to  "true"
-(case-insensitive), the system-level prefixes will still also be
-searched for site-packages; otherwise they won't.  If the system-level
-prefixes are not included then the user site prefixes are also implicitly
-not searched for site-packages.
-
-All of the resulting site-specific directories, if they exist, are
-appended to sys.path, and also inspected for path configuration
-files.
-
-A path configuration file is a file whose name has the form
-<package>.pth; its contents are additional directories (one per line)
-to be added to sys.path.  Non-existing directories (or
-non-directories) are never added to sys.path; no directory is added to
-sys.path more than once.  Blank lines and lines beginning with
-'#' are skipped. Lines starting with 'import' are executed.
-
-For example, suppose sys.prefix and sys.exec_prefix are set to
-/usr/local and there is a directory /usr/local/lib/python2.5/site-packages
-with three subdirectories, foo, bar and spam, and two path
-configuration files, foo.pth and bar.pth.  Assume foo.pth contains the
-following:
-
-  # foo package configuration
-  foo
-  bar
-  bletch
-
-and bar.pth contains:
-
-  # bar package configuration
-  bar
-
-Then the following directories are added to sys.path, in this order:
-
-  /usr/local/lib/python2.5/site-packages/bar
-  /usr/local/lib/python2.5/site-packages/foo
-
-Note that bletch is omitted because it doesn't exist; bar precedes foo
-because bar.pth comes alphabetically before foo.pth; and spam is
-omitted because it is not mentioned in either path configuration file.
-
-The readline module is also automatically configured to enable
-completion for systems that support it.  This can be overridden in
-sitecustomize, usercustomize or PYTHONSTARTUP.  Starting Python in
-isolated mode (-I) disables automatic readline configuration.
-
-After these operations, an attempt is made to import a module
-named sitecustomize, which can perform arbitrary additional
-site-specific customizations.  If this import fails with an
-ImportError exception, it is silently ignored.
+the key "include-system-site-packages" set to "true" (case-insensitive),
+the system-level prefixes will still also be searched for site-packages;
+otherwise they won't.
+
+Two kinds of configuration files are processed in each site-packages
+directory:
+
+- <name>.pth files extend sys.path with additional directories (one per
+  line).  Lines starting with "import" are deprecated (see PEP 829).
+
+- <name>.start files specify startup entry points using the
+  pkg.mod:callable syntax.  These are resolved via pkgutil.resolve_name()
+  and called with no arguments.
+
+All .pth path extensions are applied before any .start entry points are
+executed, ensuring that paths are available before startup code runs.
+
+See the documentation for the site module for full details:
+https://docs.python.org/3/library/site.html
 """
 
 import sys