docs: document linked lists

Add example-driven documentation for the kernel's generic linked list
data structure. This includes discussion of situations where linked
lists are likely inappropriate, and references to further reading.

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://lore.kernel.org/r/20250714-linked-list-docs-v3-1-56c461580866@collabora.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/core-api/index.rst

@@ -54,6 +54,7 @@ Library functionality that is used throughout the kernel.
    union_find
    min_heap
    parser
+   list
 
 Low level entry and exit
 ========================

Documentation/core-api/kernel-api.rst

@@ -3,12 +3,6 @@ The Linux Kernel API
 ====================
 
 
-List Management Functions
-=========================
-
-.. kernel-doc:: include/linux/list.h
-   :internal:
-
 Basic C Library Functions
 =========================