[3.14] Docs: an "improve this page" feature (GH-144939)

* Docs: a start on an 'improve this page' feature

* pr feedback: simplify the link, and don't scare people with the cla

* pr feedback answered

- use the actual page URL
- tighten the wording

* fix the improve link on the improve page

* news item

* Update Doc/improve-page.rst

Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>

* fix whitespace

* A nojs version of the page

* comments to help people keep the two pages in sync

* protect against XSS

* use template for issues from the nojs page

* use the template from the JS page as well

* give the docs issue template a fillable description field

* ugh, getting sloppy

* remove more sloppiness

---------
(cherry picked from commit 7a7521b)

Co-authored-by: Ned Batchelder <ned@nedbatchelder.com>
Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>

Author: nedbat

Doc/improve-page-nojs.rst

@@ -0,0 +1,29 @@
+:orphan:
+
+****************************
+Improve a documentation page
+****************************
+
+.. This is the no-javascript version of this page. The one most people
+   will see (with JavaScript enabled) is improve-page.rst. If you edit
+   this page, please also edit that one, and vice versa.
+
+.. only:: html and not epub
+
+We are always interested to hear ideas about improvements to the documentation.
+
+.. only:: translation
+
+   If the bug or suggested improvement concerns the translation of this
+   documentation, open an issue or edit the page in
+   `translation's repository <TRANSLATION_REPO_>`_ instead.
+
+You have a few ways to ask questions or suggest changes:
+
+- You can start a discussion about the page on the Python discussion forum.
+  This link will start a topic in the Documentation category:
+  `New Documentation topic <https://discuss.python.org/new-topic?category=documentation>`_.
+
+- You can open an issue on the Python GitHub issue tracker. This link will
+  create a new issue with the "docs" label:
+  `New docs issue <https://github.com/python/cpython/issues/new?template=documentation.yml>`_.

Doc/improve-page.rst

@@ -0,0 +1,65 @@
+:orphan:
+
+****************************
+Improve a documentation page
+****************************
+
+.. This is the JavaScript-enabled version of this page. Another version
+   (for those with JavaScript disabled) is improve-page-nojs.rst. If you
+   edit this page, please also edit that one, and vice versa.
+
+.. only:: html and not epub
+
+   .. raw:: html
+
+      <script>
+         function applyReplacements(text, params) {
+            return text
+               .replace(/PAGETITLE/g, params.get('pagetitle'))
+               .replace(/PAGEURL/g, params.get('pageurl'))
+               .replace(/PAGESOURCE/g, params.get('pagesource'));
+         }
+
+         document.addEventListener('DOMContentLoaded', () => {
+            const params = new URLSearchParams(window.location.search);
+            const walker = document.createTreeWalker(
+               document.body,
+               NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT,
+               null
+            );
+
+            while (walker.nextNode()) {
+               const node = walker.currentNode;
+
+               if (node.nodeType === Node.TEXT_NODE) {
+                  node.textContent = applyReplacements(node.textContent, params)
+               } else if (node.nodeName === 'A' && node.href) {
+                  node.setAttribute('href', applyReplacements(node.getAttribute('href'), params));
+               }
+            }
+         });
+      </script>
+
+We are always interested to hear ideas about improvements to the documentation.
+
+You were reading "PAGETITLE" at `<PAGEURL>`_.  The source for that page is on
+`GitHub <https://github.com/python/cpython/blob/main/Doc/PAGESOURCE?plain=1>`_.
+
+.. only:: translation
+
+   If the bug or suggested improvement concerns the translation of this
+   documentation, open an issue or edit the page in
+   `translation's repository <TRANSLATION_REPO_>`_ instead.
+
+You have a few ways to ask questions or suggest changes:
+
+- You can start a discussion about the page on the Python discussion forum.
+  This link will start a pre-populated topic:
+  `Question about page "PAGETITLE" <https://discuss.python.org/new-topic?category=documentation&title=Question+about+page+%22PAGETITLE%22&body=About+the+page+at+PAGEURL%3A>`_.
+
+- You can open an issue on the Python GitHub issue tracker. This link will
+  create a new pre-populated issue:
+  `Docs: problem with page "PAGETITLE" <https://github.com/python/cpython/issues/new?template=documentation.yml&title=Docs%3A+problem+with+page+%22PAGETITLE%22&description=The+page+at+PAGEURL+has+a+problem%3A>`_.
+
+- You can `edit the page on GitHub <https://github.com/python/cpython/blob/main/Doc/PAGESOURCE?plain=1>`_
+  to open a pull request and begin the contribution process.

Doc/tools/templates/customsourcelink.html

@@ -1,10 +1,25 @@
 {%- if show_source and has_source and sourcename %}
+  <script>
+    document.addEventListener('DOMContentLoaded', () => {
+        const title = document.querySelector('meta[property="og:title"]').content;
+        const elements = document.querySelectorAll('.improvepage');
+        const pageurl = window.location.href.split('?')[0];
+        elements.forEach(element => {
+            const url = new URL(element.href.split('?')[0].replace("-nojs", ""));
+            url.searchParams.set('pagetitle', title);
+            url.searchParams.set('pageurl', pageurl);
+            url.searchParams.set('pagesource', "{{ pagename }}.rst");
+            element.href = url.toString();
+        });
+    });
+  </script>
   <div role="note" aria-label="source link">
     <h3>{{ _('This page') }}</h3>
     <ul class="this-page-menu">
       <li><a href="{{ pathto('bugs') }}">{% trans %}Report a bug{% endtrans %}</a></li>
+      <li><a class="improvepage" href="{{ pathto('improve-page-nojs') }}">{% trans %}Improve this page{% endtrans %}</a></li>
       <li>
-        <a href="https://github.com/python/cpython/blob/main/Doc/{{ sourcename|replace('.rst.txt', '.rst') }}?plain=1"
+        <a href="https://github.com/python/cpython/blob/main/Doc/{{ pagename }}.rst?plain=1"
             rel="nofollow">{{ _('Show source') }}
         </a>
       </li>

Misc/NEWS.d/next/Documentation/2025-08-02-18-59-01.gh-issue-136246.RIK7nE.rst

@@ -0,0 +1,3 @@
+A new "Improve this page" link is available in the left-hand sidebar of the
+docs, offering links to create GitHub issues, discussion forum posts, or
+pull requests.