Issue #26240: Merge subprocess doc string from 3.5 into 3.6

diff --cc Lib/subprocess.py
index 9df93182451cd226fdbebfb347405ed064bbd42a,502e26b9c42c3f36ae534210396d88ad66d15e26..e742a4e199b25be32da1862d164aca38b3ee6fbe
--- 1/Lib/subprocess.py
--- 2/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@@ -841,7 -518,46 +538,49 @@@ _PLATFORM_DEFAULT_CLOSE_FDS = object(
  
  
  class Popen(object):
+     """ Execute a child program in a new process.
+ 
+     For a complete description of the arguments see the Python documentation.
  
+     Arguments:
+       args: A string, or a sequence of program arguments.
+ 
+       bufsize: supplied as the buffering argument to the open() function when
+           creating the stdin/stdout/stderr pipe file objects
+ 
+       executable: A replacement program to execute.
+ 
+       stdin, stdout and stderr: These specify the executed programs' standard
+           input, standard output and standard error file handles, respectively.
+ 
+       preexec_fn: (POSIX only) An object to be called in the child process
+           just before the child is executed.
+ 
+       close_fds: Controls closing or inheriting of file descriptors.
+ 
+       shell: If true, the command will be executed through the shell.
+ 
+       cwd: Sets the current directory before the child is executed.
+ 
+       env: Defines the environment variables for the new process.
+ 
+       universal_newlines: If true, use universal line endings for file
+           objects stdin, stdout and stderr.
+ 
+       startupinfo and creationflags (Windows only)
+ 
+       restore_signals (POSIX only)
+ 
+       start_new_session (POSIX only)
+ 
+       pass_fds (POSIX only)
+ 
++      encoding and errors: Text mode encoding and error handling to use for
++          file objects stdin, stdout and stderr.
++
+     Attributes:
+         stdin, stdout, stderr, pid, returncode
+     """
      _child_created = False  # Set here since __del__ checks it
  
      def __init__(self, args, bufsize=-1, executable=None,

diff --cc Misc/ACKS
Simple merge