docs: Fix broken links to user guide (pola-rs#19989)

crates/polars/src/docs/lazy.rs

@@ -103,7 +103,7 @@
 //!
 //! ## Groupby
 //!
-//! This example is from the polars [user guide](https://docs.pola.rs/user-guide/concepts/contexts/#group_by-aggregation).
+//! This example is from the polars [user guide](https://docs.pola.rs/user-guide/concepts/expressions-and-contexts/#group_by-and-aggregations).
 //!
 //! ```
 //! use polars::prelude::*;

crates/polars/src/lib.rs

@@ -145,7 +145,7 @@
 //! (Note that within an expression there may be more parallelization going on).
 //!
 //! Understanding Polars expressions is most important when starting with the Polars library. Read more
-//! about them in the [user guide](https://docs.pola.rs/user-guide/concepts/expressions).
+//! about them in the [user guide](https://docs.pola.rs/user-guide/expressions).
 //!
 //! ### Eager
 //! Read more in the pages of the following data structures /traits.

docs/source/user-guide/plugins/index.md

@@ -0,0 +1,5 @@
+# Plugins
+
+In this chapter you will learn how to write plugins in order to extend the Polars API.
+
+- [Your first Polars plugin](your-first-polars-plugin.md)

mkdocs.yml

@@ -68,6 +68,7 @@ nav:
       - user-guide/io/bigquery.md
       - user-guide/io/hugging-face.md
     - Plugins:
+      - user-guide/plugins/index.md
       - user-guide/plugins/your-first-polars-plugin.md
     - SQL:
       - user-guide/sql/intro.md

py-polars/docs/source/reference/plugins.rst

@@ -4,7 +4,7 @@ Plugins
 .. currentmodule:: polars
 
 Plugins allow for extending Polars' functionality. See the
-`user guide <https://docs.pola.rs/user-guide/expressions/plugins/>`_ for more information
+`user guide <https://docs.pola.rs/user-guide/plugins/>`_ for more information
 and resources.
 
 Available plugin utility functions are:

py-polars/polars/expr/expr.py

@@ -10561,7 +10561,7 @@ def register_plugin(
         .. deprecated:: 0.20.16
             Use :func:`polars.plugins.register_plugin_function` instead.
 
-        See the `user guide <https://docs.pola.rs/user-guide/expressions/plugins/>`_
+        See the `user guide <https://docs.pola.rs/user-guide/plugins/>`_
         for more information about plugins.
 
         Warnings

py-polars/polars/plugins.py

@@ -36,7 +36,7 @@ def register_plugin_function(
     """
     Register a plugin function.
 
-    See the `user guide <https://docs.pola.rs/user-guide/expressions/plugins/>`_
+    See the `user guide <https://docs.pola.rs/user-guide/plugins/>`_
     for more information about plugins.
 
     Parameters