[PATCH 3/4] api docs: document that BUG() emits a trace2 error event

Correct documentation added in e544221d97a (trace2:
Documentation/technical/api-trace2.txt, 2019-02-22) to state that
calling BUG() also emits an "error" event. See ee4512ed481 (trace2:
create new combined trace facility, 2019-02-22) for the initial
implementation.

The BUG() function did not emit an event then however, that was only
changed later in 0a9dde4a04c (usage: trace2 BUG() invocations,
2021-02-05), that commit changed the code, but didn't update any of
the docs.

Let's also add a cross-reference from api-error-handling.txt.

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---
 Documentation/technical/api-error-handling.txt | 3 +++
 Documentation/technical/api-trace2.txt         | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Documentation/technical/api-error-handling.txt b/Documentation/technical/api-error-handling.txt
index 71486abb2f0..8be4f4d0d6a 100644
--- a/Documentation/technical/api-error-handling.txt
+++ b/Documentation/technical/api-error-handling.txt

@@ -23,6 +23,9 @@ various kinds.
   without running into too many problems.  Like `error`, it
   returns -1 after reporting the situation to the caller.
 
+These reports will be logged via the trace2 facility. See the "error"
+event in link:api-trace2.txt[trace2 API].
+
 Customizable error handlers
 ---------------------------
 

diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt
index c65ffafc485..3f52f981a2d 100644
--- a/Documentation/technical/api-trace2.txt
+++ b/Documentation/technical/api-trace2.txt

@@ -465,7 +465,7 @@ completed.)
 ------------
 
 `"error"`::
-	This event is emitted when one of the `error()`, `die()`,
+	This event is emitted when one of the `BUG()`, `error()`, `die()`,
 	`warning()`, or `usage()` functions are called.
 +
 ------------

-- 
2.31.1.445.g91d8e479b0a