Add full API docs and improve the UX of navigating them (#17485)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tests/conftest.py

@@ -112,11 +112,11 @@ class AudioTestAssets(list[AudioAsset]):
 
 
 IMAGE_ASSETS = ImageTestAssets()
-"""Singleton instance of :class:`ImageTestAssets`."""
+"""Singleton instance of {class}`ImageTestAssets`."""
 VIDEO_ASSETS = VideoTestAssets()
-"""Singleton instance of :class:`VideoTestAssets`."""
+"""Singleton instance of {class}`VideoTestAssets`."""
 AUDIO_ASSETS = AudioTestAssets()
-"""Singleton instance of :class:`AudioTestAssets`."""
+"""Singleton instance of {class}`AudioTestAssets`."""
 
 
 @pytest.fixture(scope="function", autouse=True)
@@ -724,7 +724,7 @@ def hf_runner():
 class VllmRunner:
     """
     The default value of some arguments have been modified from
-    :class:`~vllm.LLM` as follows:
+    {class}`~vllm.LLM` as follows:
 
     - `trust_remote_code`: Set to `True` instead of `False` for convenience.
     - `seed`: Set to `0` instead of `None` for test reproducibility.