docs(python): Update GPU engine installation instructions to remove `…

…--extra-index-url` from CUDA 12 packages (#20381)

Co-authored-by: Bradley Dice <[email protected]>

docs/source/user-guide/gpu-support.md

@@ -20,12 +20,12 @@ You can install the GPU backend for Polars with a feature flag as part of a norm
 === ":fontawesome-brands-python: Python"
 
 ```bash
-pip install --extra-index-url=https://pypi.nvidia.com polars[gpu]
+pip install polars[gpu]
 ```
 
 !!! note Installation on a CUDA 11 system
 
-    If you have CUDA 11, the installation line is slightly more complicated: the relevant GPU package must be requested by hand.
+    If you have CUDA 11, the installation line also needs the NVIDIA package index to get the CUDA 11 package.
 
     === ":fontawesome-brands-python: Python"
     ```bash

docs/source/user-guide/installation.md

@@ -98,9 +98,7 @@ pip install 'polars[numpy,fsspec]'
 
 !!! note
 
-    To install the GPU engine, you need to pass
-    `--extra-index-url=https://pypi.nvidia.com` to `pip`. See [GPU
-    support](gpu-support.md) for more detailed instructions and
+    See [GPU support](gpu-support.md) for more detailed instructions and
     prerequisites.
 
 #### Interoperability

py-polars/polars/lazyframe/frame.py

@@ -2019,7 +2019,7 @@ def collect(
                 err_prefix="GPU engine requested, but required package",
                 install_message=(
                     "Please install using the command "
-                    "`pip install --extra-index-url=https://pypi.nvidia.com cudf-polars-cu12` "
+                    "`pip install cudf-polars-cu12` "
                     "(or `pip install --extra-index-url=https://pypi.nvidia.com cudf-polars-cu11` "
                     "if your system has a CUDA 11 driver)."
                 ),