Documentation: Add documentation of SCHED_DUMP_TASKS and SCHED_DUMP_STACK

Add documentation for controlling the crash dump verbosity.

Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>

Documentation/debugging/disabling_stackdumpdebug.rst

@@ -12,4 +12,38 @@ the board configuration:
 
 .. code-block:: c
 
-    CONFIG_ARCH_STACKDUMP=n
+    CONFIG_ARCH_STACKDUMP=n
+
+Reducing the Crash Dump Verbosity
+=================================
+
+In addition to ``CONFIG_ARCH_STACKDUMP``, which controls whether the
+architecture-specific stack dump is produced at all, two finer-grained
+options are available to tune how verbose the assertion / crash output
+from ``sched/misc/assert.c`` is. Disabling them is useful to reduce
+flash usage on small targets and to keep the crash log short.
+
+Both options default to ``y`` unless ``CONFIG_DEFAULT_SMALL`` is
+selected, in which case they default to ``n``.
+
+CONFIG_SCHED_DUMP_TASKS
+-----------------------
+
+Controls whether the per-task information table (task list with PID,
+priority, scheduling policy, stack usage, state, etc.) is printed as
+part of the crash dump.
+
+.. code-block:: c
+
+    CONFIG_SCHED_DUMP_TASKS=n   /* Omit the task table from the crash dump */
+
+CONFIG_SCHED_DUMP_STACK
+-----------------------
+
+Controls whether the contents of each stack (IRQ / kernel / user) are
+dumped as hex words. When disabled, only the base address and size of
+each stack are printed; the stack memory itself is not dumped.
+
+.. code-block:: c
+
+    CONFIG_SCHED_DUMP_STACK=n   /* Omit the hex stack contents from the dump */