[damned-lies] Refs #58 - Add .docbook for fallback listing

[Claude Paroz <claudep src gnome org>]

commit 64c9438bb517f378b4197bc96cc2add93af0d01f
Author: Claude Paroz <claude 2xlibre net>
Date:   Fri Oct 30 10:44:21 2020 +0100

    Refs #58 - Add .docbook for fallback listing

 stats/utils.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/stats/utils.py b/stats/utils.py
index e9ddaff3..f05a8c75 100644
--- a/stats/utils.py
+++ b/stats/utils.py
@@ -103,9 +103,9 @@ class DocFormat:
 
         source_list = self.makefile.read_variable(self.include_var)
         if not source_list:
-            suffix = '.page' if self.format == 'mallard' else '.xml'
+            suffix = ['.page'] if self.format == 'mallard' else ['.xml', '.docbook']
             # Fallback to directory listing
-            return [f for f in self.list_C_files() if f.suffix == suffix]
+            return [f for f in self.list_C_files() if f.suffix in suffix]
         if isinstance(source_list, str):
             sources += source_list.split()
         elif source_list: