ext4, doc: remove unnecessary escaping

Signed-off-by: Wang Jianjian <wangjianjian3@huawei.com>
Link: https://lore.kernel.org/r/20220520022255.2120576-2-wangjianjian3@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4, doc: fix incorrect h_reserved size

According to document and code, ext4_xattr_header's size is 32 bytes, so
h_reserved size should be 3.

Signed-off-by: Wang Jianjian <wangjianjian3@huawei.com>
Link: https://lore.kernel.org/r/92fcc3a6-7d77-8c09-4126-377fcb4c46a5@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

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>