kernel: remove k_alert API

This API was used in only one place in non-test code.  See whether we
can remove it.

Closes zephyrproject-rtos#12232

Signed-off-by: Peter A. Bigot <[email protected]>

Author: pabigot

doc/api/kernel_api.rst

@@ -109,16 +109,6 @@ with basic priority inheritance.
 .. doxygengroup:: mutex_apis
    :project: Zephyr
 
-Alerts
-******
-
-Alerts enable an application to perform asynchronous signaling,
-somewhat akin to Unix-style signals.
-(See :ref:`alerts_v2`.)
-
-.. doxygengroup:: alert_apis
-   :project: Zephyr
-
 FIFOs
 *****
 

doc/kernel/other/interrupts.rst

@@ -166,12 +166,8 @@ processing to a thread.
 * An ISR can signal a helper thread to do interrupt-related processing
   using a kernel object, such as a fifo, lifo, or semaphore.
 
-* An ISR can signal an alert which causes the system workqueue thread
-  to execute an associated alert handler function.
-  (See :ref:`alerts_v2`.)
-
 * An ISR can instruct the system workqueue thread to execute a work item.
-  (See TBD.)
+  (See :ref:`workqueues_v2`.)
 
 When an ISR offloads work to a thread, there is typically a single context
 switch to that thread when the ISR completes, allowing interrupt-related

doc/kernel/synchronization/alerts.rst

@@ -11,4 +11,3 @@ of different threads, or the operation of an ISR and a thread.
 
    semaphores.rst
    mutexes.rst
-   alerts.rst

doc/kernel/synchronization/synchronization.rst

@@ -20,7 +20,6 @@ extern struct k_mem_slab *_trace_list_k_mem_slab;
 extern struct k_mem_pool *_trace_list_k_mem_pool;
 extern struct k_sem      *_trace_list_k_sem;
 extern struct k_mutex    *_trace_list_k_mutex;
-extern struct k_alert    *_trace_list_k_alert;
 extern struct k_fifo     *_trace_list_k_fifo;
 extern struct k_lifo     *_trace_list_k_lifo;
 extern struct k_stack    *_trace_list_k_stack;