Update outdated Pillow links

docs/contributing/developing.md

@@ -17,7 +17,7 @@ If you'd prefer to set up all the components manually, read on. These instructio
 The preferred way to install the correct version of Node is to use [Fast Node Manager (fnm)](https://github.com/Schniz/fnm), which will always align the version with the supplied `.nvmrc` file in the root of the project. To ensure you are running the correct version of Node, run `fnm install` from the project root.
 Alternatively, you can install [Node.js](https://nodejs.org/) directly, ensure you install the version as declared in the project's root `.nvmrc` file.
 
-You will also need to install the **libjpeg** and **zlib** libraries, if you haven't done so already - see Pillow's [platform-specific installation instructions](https://pillow.readthedocs.io/en/stable/installation.html#external-libraries).
+You will also need to install the **libjpeg** and **zlib** libraries, if you haven't done so already - see Pillow's [platform-specific installation instructions](https://pillow.readthedocs.io/en/stable/installation/building-from-source.html#external-libraries).
 
 Fork the [the Wagtail codebase](https://github.com/wagtail/wagtail) and clone the forked copy:
 

docs/getting_started/integrating_into_django.md

@@ -12,7 +12,7 @@ Wagtail is currently compatible with Django 4.2, 5.0 and 5.1. First, install the
 pip install wagtail
 ```
 
-or add the package to your existing requirements file. This will also install the **Pillow** library as a dependency, which requires libjpeg and zlib - see Pillow's [platform-specific installation instructions](https://pillow.readthedocs.io/en/stable/installation.html#external-libraries).
+or add the package to your existing requirements file. This will also install the **Pillow** library as a dependency, which requires libjpeg and zlib - see Pillow's [platform-specific installation instructions](https://pillow.readthedocs.io/en/stable/installation/building-from-source.html#external-libraries).
 
 ## Settings
 

docs/getting_started/quick_install.md

@@ -11,7 +11,7 @@
 
 -   [Python 3](https://www.python.org/downloads/).
 -   **libjpeg** and **zlib**, libraries required for Django's **Pillow** library.
-    See Pillow's [platform-specific installation instructions](https://pillow.readthedocs.io/en/stable/installation.html#external-libraries).
+    See Pillow's [platform-specific installation instructions](https://pillow.readthedocs.io/en/stable/installation/building-from-source.html#external-libraries).
 
 ## Install Wagtail