Merge branch 'tristan/doc-fix-deprecations-1.2' into 'bst-1.2'

doc/bst2html.py: Fix deprecation warning (1.2)

See merge request !734

doc/bst2html.py

@@ -29,7 +29,7 @@ import sys
 import re
 import shlex
 import subprocess
-from collections import Mapping
+from collections.abc import Mapping
 from contextlib import contextmanager
 from tempfile import TemporaryDirectory