docs: Try fix doc build

Author: SilverRainZ

docs/_examples/ctxdir.py

@@ -0,0 +1 @@
+../../tests/roots/test-ctxdir-usage/conf.py

docs/conf.py

@@ -137,6 +137,6 @@
 def setup(app):
     app.add_object_type('event', 'event') # for intersphinx
 
-    sys.path.insert(0, os.path.abspath('../tests/roots/test-ctxdir-usage'))
-    from conf import setup as setup_ctxdir_usage_example
-    setup_ctxdir_usage_example(app)
+    sys.path.insert(0, os.path.abspath('./_examples'))
+    from ctxdir import setup as ctxdir_example_setup
+    ctxdir_example_setup(app)