Fix typo (#1280)

* fix typo

* fix typo

docs/community/pr.md

@@ -6,7 +6,7 @@
 
 > Pull requests let you tell others about changes you've pushed to a branch in a repository on GitHub. Once a pull request is opened, you can discuss and review the potential changes with collaborators and add follow-up commits before your changes are merged into the base branch.
 
-## Basic Workflow
+### Basic Workflow
 
 1. Get the most recent codebase
 2. Checkout a new branch from the master branch

mmcv/utils/registry.py

@@ -66,7 +66,8 @@ class Registry:
         >>>     pass
         >>> resnet = MODELS.build(dict(type='ResNet'))
 
-    Please refer to https://mmcv.readthedocs.io/en/latest/registry.html for
+    Please refer to
+    https://mmcv.readthedocs.io/en/latest/understand_mmcv/registry.html for
     advanced useage.
 
     Args: