Convert to "bool".

doc/user/intr.t

@@ -441,7 +441,7 @@ This directive will not cause the calling task to be preempted.
 @ifset is-C
 @findex rtems_interrupt_is_in_progress
 @example
-rtems_boolean rtems_interrupt_is_in_progress( void );
+bool rtems_interrupt_is_in_progress( void );
 @end example
 @end ifset
 

doc/user/userext.t

@@ -465,7 +465,7 @@ This extension should have a prototype similar to the following:
 @example
 rtems_extension user_fatal_error(
   Internal_errors_Source  the_source,
-  rtems_boolean           is_internal,
+  bool                    is_internal,
   uint32_t                the_error
 );
 @end example