docs: fix WARNING document not included in any toctree

Add debugging.rst to the relevant toctree to fix warning
about missing documentation inclusion in toctree.

Signed-off-by: SurajSonawane2415 <surajsonawane0215@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241002195817.22972-1-surajsonawane0215@gmail.com

Author: SurajSonawane2415

Documentation/trace/index.rst

@@ -24,6 +24,7 @@ Linux Tracing Technologies
    histogram
    histogram-design
    boottime-trace
+   debugging
    hwlat_detector
    osnoise-tracer
    timerlat-tracer