Docs: multi-disk ZIP files -> multipart ZIP files (GH-141962)

* Remove some old currentlies
* multi-disk -> multipart
* Sentence case headings
(cherry picked from commit 890fe5a)

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Author: hugovk

Doc/library/zipfile.rst

@@ -16,10 +16,10 @@ provides tools to create, read, write, append, and list a ZIP file.  Any
 advanced use of this module will require an understanding of the format, as
 defined in `PKZIP Application Note`_.
 
-This module does not currently handle multi-disk ZIP files.
+This module does not handle multipart ZIP files.
 It can handle ZIP files that use the ZIP64 extensions
 (that is ZIP files that are more than 4 GiB in size).  It supports
-decryption of encrypted files in ZIP archives, but it currently cannot
+decryption of encrypted files in ZIP archives, but it cannot
 create an encrypted file.  Decryption is extremely slow as it is
 implemented in native Python rather than C.
 
@@ -140,7 +140,7 @@ The module defines the following items:
 
 .. _zipfile-objects:
 
-ZipFile Objects
+ZipFile objects
 ---------------
 
 
@@ -208,7 +208,7 @@ ZipFile Objects
    .. note::
 
       *metadata_encoding* is an instance-wide setting for the ZipFile.
-      It is not currently possible to set this on a per-member basis.
+      It is not possible to set this on a per-member basis.
 
       This attribute is a workaround for legacy implementations which produce
       archives with names in the current locale encoding or code page (mostly
@@ -530,7 +530,7 @@ The following data attributes are also available:
 
 .. _path-objects:
 
-Path Objects
+Path objects
 ------------
 
 .. class:: Path(root, at='')
@@ -666,7 +666,7 @@ changes.
 
 .. _pyzipfile-objects:
 
-PyZipFile Objects
+PyZipFile objects
 -----------------
 
 The :class:`PyZipFile` constructor takes the same parameters as the
@@ -743,7 +743,7 @@ The :class:`PyZipFile` constructor takes the same parameters as the
 
 .. _zipinfo-objects:
 
-ZipInfo Objects
+ZipInfo objects
 ---------------
 
 Instances of the :class:`ZipInfo` class are returned by the :meth:`.getinfo` and
@@ -913,7 +913,7 @@ Instances have the following methods and attributes:
 .. _zipfile-commandline:
 .. program:: zipfile
 
-Command-Line Interface
+Command-line interface
 ----------------------
 
 The :mod:`zipfile` module provides a simple command-line interface to interact
@@ -988,7 +988,7 @@ From file itself
 Decompression may fail due to incorrect password / CRC checksum / ZIP format or
 unsupported compression method / decryption.
 
-File System limitations
+File system limitations
 ~~~~~~~~~~~~~~~~~~~~~~~
 
 Exceeding limitations on different file systems can cause decompression failed.