docs: Add more manuals to the PDF build

There were a few manuals that weren't being built in PDF format, but
there's no reason not to...

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/core-api/conf.py b/Documentation/core-api/conf.py
index fed87ab..db1f765 100644
--- a/Documentation/core-api/conf.py
+++ b/Documentation/core-api/conf.py
@@ -3,3 +3,8 @@
 project = "Core-API Documentation"
 
 tags.add("subproject")
+
+latex_documents = [
+    ('index', 'core-api.tex', project,
+     'The kernel development community', 'manual'),
+]