[Doc][4/N] Reorganize API Reference (#11843)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

docs/source/api/offline_inference/index.md

@@ -0,0 +1,9 @@
+# Offline Inference
+
+```{toctree}
+:caption: Contents
+:maxdepth: 1
+
+llm
+llm_inputs
+```

docs/source/api/offline_inference/llm.md

@@ -0,0 +1,7 @@
+# LLM Class
+
+```{eval-rst}
+.. autoclass:: vllm.LLM
+    :members:
+    :show-inheritance:
+```

docs/source/api/offline_inference/llm_inputs.md

@@ -0,0 +1,19 @@
+# LLM Inputs
+
+```{eval-rst}
+.. autodata:: vllm.inputs.PromptType
+```
+
+```{eval-rst}
+.. autoclass:: vllm.inputs.TextPrompt
+    :show-inheritance:
+    :members:
+    :member-order: bysource
+```
+
+```{eval-rst}
+.. autoclass:: vllm.inputs.TokensPrompt
+    :show-inheritance:
+    :members:
+    :member-order: bysource
+```