bpo-35397: Remove deprecation and document urllib.parse.unwrap (GH-11481)

diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
index afce8eb..f6ce9cb 100644
--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -101,7 +101,7 @@
 
 from urllib.error import URLError, HTTPError, ContentTooShortError
 from urllib.parse import (
-    urlparse, urlsplit, urljoin, _unwrap, quote, unquote,
+    urlparse, urlsplit, urljoin, unwrap, quote, unquote,
     _splittype, _splithost, _splitport, _splituser, _splitpasswd,
     _splitattr, _splitquery, _splitvalue, _splittag, _to_bytes,
     unquote_to_bytes, urlunparse)
@@ -349,7 +349,7 @@
     @full_url.setter
     def full_url(self, url):
         # unwrap('<URL:type://host/path>') --> 'type://host/path'
-        self._full_url = _unwrap(url)
+        self._full_url = unwrap(url)
         self._full_url, self.fragment = _splittag(self._full_url)
         self._parse()
 
@@ -1727,7 +1727,7 @@
     # External interface
     def open(self, fullurl, data=None):
         """Use URLopener().open(file) instead of open(file, 'r')."""
-        fullurl = _unwrap(_to_bytes(fullurl))
+        fullurl = unwrap(_to_bytes(fullurl))
         fullurl = quote(fullurl, safe="%/:=&?~#+!$,;'@()*[]|")
         if self.tempcache and fullurl in self.tempcache:
             filename, headers = self.tempcache[fullurl]
@@ -1775,7 +1775,7 @@
     def retrieve(self, url, filename=None, reporthook=None, data=None):
         """retrieve(url) returns (filename, headers) for a local object
         or (tempfilename, headers) for a remote object."""
-        url = _unwrap(_to_bytes(url))
+        url = unwrap(_to_bytes(url))
         if self.tempcache and url in self.tempcache:
             return self.tempcache[url]
         type, url1 = _splittype(url)