[docs] Fix dgl doc display problem. (#7691)

docs/source/conf.py

@@ -81,7 +81,10 @@
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This pattern also affects html_static_path and html_extra_path.
-exclude_patterns = []
+exclude_patterns = [
+    "tutorials/**/*.ipynb",
+    "tutorials/**/*.py",
+]
 
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = None