[Doc] Move demo to Get Started (#670)

* Rename 0_demo.md to demo.md

* Move demo to Get Started

* Update Verification correspondingly

docs/getting_started.md

@@ -215,9 +215,7 @@ PYTHONPATH="$(dirname $0)/..":$PYTHONPATH
 
 # Verification
 
-## Demo
-
-### Point cloud demo
+## Verify with point cloud demo
 
 We provide several demo scripts to test a single sample. Pre-trained models can be downloaded from [model zoo](model_zoo.md). To test a single-modality 3D detection on point cloud scenes:
 
@@ -273,7 +271,7 @@ Examples:
 to_ply('./test.obj', './test.ply', 'obj')
 ```
 
-More demos about single/multi-modality and indoor/outdoor 3D detection can be found in [demo](0_demo.md).
+More demos about single/multi-modality and indoor/outdoor 3D detection can be found in [demo](demo.md).
 
 ## High-level APIs for testing point clouds
 

docs/index.rst

@@ -6,6 +6,7 @@ Welcome to MMDetection3D's documentation!
    :caption: Get Started
 
    getting_started.md
+   demo.md
    model_zoo.md
    data_preparation.md
 
@@ -13,7 +14,6 @@ Welcome to MMDetection3D's documentation!
    :maxdepth: 2
    :caption: Quick Run
 
-   0_demo.md
    1_exist_data_model.md
    2_new_data_model.md