docs: Instruct LaTeX to cope with deeper nesting

The addition of the XFS online fsck documentation starting with
commit a8f6c2e5 ("xfs: document the motivation for online fsck design")
added a deeper level of nesting than LaTeX is prepared to deal with.  That
caused a pdfdocs build failure with the helpful "Too deeply nested" error
message buried deeply in Documentation/output/filesystems.log.

Increase the "maxlistdepth" parameter to instruct LaTeX that it needs to
deal with the deeper nesting whether it wants to or not.
Suggested-by: Akira Yokosawa <akiyks@gmail.com>
Tested-by: Akira Yokosawa <akiyks@gmail.com>
Cc: stable@vger.kernel.org # v6.4+
Link: https://lore.kernel.org/linux-doc/67f6ac60-7957-4b92-9d72-a08fbad0e028@gmail.com/Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/conf.py

@@ -388,6 +388,12 @@ latex_elements = {
         verbatimhintsturnover=false,
     ''',
 
+    #
+    # Some of our authors are fond of deep nesting; tell latex to
+    # cope.
+    #
+    'maxlistdepth': '10',
+
     # For CJK One-half spacing, need to be in front of hyperref
     'extrapackages': r'\usepackage{setspace}',