docs: promote the ext4 data structures book to top level

Move the ext4 data structures book to Documentation/filesystems/ext4/
since the administrative information moved elsewhere.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Documentation/conf.py

@@ -385,8 +385,8 @@ latex_documents = [
      'The kernel development community', 'manual'),
     ('admin-guide/ext4', 'ext4-admin-guide.tex', 'ext4 Administration Guide',
      'ext4 Community', 'manual'),
-    ('filesystems/ext4/index', 'ext4.tex', 'ext4 Filesystem',
-     'ext4 Filesystem Developers', 'manual'),
+    ('filesystems/ext4/index', 'ext4-data-structures.tex',
+     'ext4 Data Structures and Algorithms', 'ext4 Community', 'manual'),
     ('gpu/index', 'gpu.tex', 'Linux GPU Driver Developer\'s Guide',
      'The kernel development community', 'manual'),
     ('input/index', 'linux-input.tex', 'The Linux input driver subsystem',

Documentation/filesystems/ext4/index.rst

 .. SPDX-License-Identifier: GPL-2.0
 
-===============
-ext4 Filesystem
-===============
-
-General usage and on-disk artifacts writen by ext4.  More documentation may
-be ported from the wiki as time permits.  This should be considered the
-canonical source of information as the details here have been reviewed by
-the ext4 community.
+===================================
+ext4 Data Structures and Algorithms
+===================================
 
 .. toctree::
-   :maxdepth: 5
+   :maxdepth: 6
    :numbered:
 
-   ondisk/index
+   about.rst
+   overview.rst
+   globals.rst
+   dynamic.rst

Documentation/filesystems/ext4/ondisk/index.rst

-.. SPDX-License-Identifier: GPL-2.0
-
-==============================
-Data Structures and Algorithms
-==============================
-.. include:: about.rst
-.. include:: overview.rst
-.. include:: globals.rst
-.. include:: dynamic.rst