docs: update sglang installation guide (#11659)

docs/get_started/install.md

@@ -12,7 +12,7 @@ It is recommended to use uv for faster installation:
 ```bash
 pip install --upgrade pip
 pip install uv
-uv pip install "sglang[all]>=0.5.3.post1"
+uv pip install sglang --upgrade
 ```
 
 **Quick fixes to common problems**
@@ -29,7 +29,7 @@ cd sglang
 
 # Install the python packages
 pip install --upgrade pip
-pip install -e "python[all]"
+pip install -e "python"
 ```
 
 **Quick fixes to common problems**