bpo-43651: Fix EncodingWarning in pydoc. (GH-25644)

Author: methane

Lib/pydoc.py

@@ -1594,9 +1594,10 @@ def plain(text):
 def pipepager(text, cmd):
     """Page through text by feeding it to another program."""
     import subprocess
-    proc = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE)
+    proc = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE,
+                            errors='backslashreplace')
     try:
-        with io.TextIOWrapper(proc.stdin, errors='backslashreplace') as pipe:
+        with proc.stdin as pipe:
             try:
                 pipe.write(text)
             except KeyboardInterrupt: