trace-events: Shorten file names in comments

We spell out sub/dir/ in sub/dir/trace-events' comments pointing to
source files.  That's because when trace-events got split up, the
comments were moved verbatim.

Delete the sub/dir/ part from these comments.  Gets rid of several
misspellings.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190314180929.27722-3-armbru@redhat.com
Message-Id: <20190314180929.27722-3-armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/qapi/trace-events b/qapi/trace-events
index b123c5e..5eb4afa 100644
--- a/qapi/trace-events
+++ b/qapi/trace-events
@@ -1,6 +1,6 @@
 # See docs/devel/tracing.txt for syntax documentation.
 
-# qapi/qapi-visit-core.c
+# qapi-visit-core.c
 visit_free(void *v) "v=%p"
 visit_complete(void *v, void *opaque) "v=%p opaque=%p"