docs: Adds syscall tracing to tracing docs

Tracing guide in the docs was missing references to the added tracing
syscall macro hooks. This adds those.

Signed-off-by: Tom Burdick <thomas.burdick@intel.com>

doc/guides/debug_tools/tracing/index.rst

@@ -471,3 +471,8 @@ Object tracking
 ===============
 
 .. doxygengroup:: subsys_tracing_object_tracking
+
+Syscalls
+========
+
+.. doxygengroup:: subsys_tracing_apis_syscall

include/tracing/tracing_syscall.h

@@ -32,8 +32,8 @@
  * @brief Trace syscall exit
  * @param id Syscall ID (as defined in the generated syscall_list.h)
  * @param name Syscall name as a token (ex: k_thread_create)
- * @param ... Other parameters passed to the syscall, if the syscall has a return, the return value
- *            is the last parameter in the list
+ * @param ... Other parameters passed to the syscall, if the syscall has a
+ *            return, the return value is the last parameter in the list
  */
 #define sys_port_trace_syscall_exit(id, name, ...)