[doc][mkdocs] Add edit button to documentation (#19637)

Signed-off-by: reidliu41 <reid201711@gmail.com>
Co-authored-by: reidliu41 <reid201711@gmail.com>

docs/mkdocs/javascript/edit_and_feedback.js

+/**
+ * edit_and_feedback.js
+ *
+ * Enhances MkDocs Material docs pages by:
+ *
+ * 1. Adding a "Question? Give us feedback" link
+ *    below the "Edit" button.
+ *
+ *    - The link opens a GitHub issue with a template,
+ *      auto-filled with the current page URL and path.
+ *
+ * 2. Ensuring the edit button opens in a new tab
+ *    with target="_blank" and rel="noopener".
+ */
+document.addEventListener("DOMContentLoaded", function () {
+  const url = window.location.href;
+  const page = document.body.dataset.mdUrl || location.pathname;
+
+  const feedbackLink = document.createElement("a");
+  feedbackLink.href = `https://github.com/vllm-project/vllm/issues/new?template=100-documentation.yml&title=${encodeURIComponent(
+    `[Docs] Feedback for \`${page}\``
+  )}&body=${encodeURIComponent(`📄 **Reference:**\n${url}\n\n📝 **Feedback:**\n_Your response_`)}`;
+  feedbackLink.target = "_blank";
+  feedbackLink.rel = "noopener";
+  feedbackLink.title = "Provide feedback";
+  feedbackLink.className = "md-content__button";
+  feedbackLink.innerHTML = `
+  <svg
+    xmlns="http://www.w3.org/2000/svg"
+    height="24px"
+    viewBox="0 -960 960 960"
+    width="24px"
+    fill="currentColor"
+  >
+    <path d="M280-280h280v-80H280v80Zm0-160h400v-80H280v80Zm0-160h400v-80H280v80Zm-80 480q-33 0-56.5-23.5T120-200v-560q0-33 23.5-56.5T200-840h560q33 0 56.5 23.5T840-760v560q0 33-23.5 56.5T760-120H200Zm0-80h560v-560H200v560Zm0-560v560-560Z"/>
+  </svg>
+`;
+
+  const editButton = document.querySelector('.md-content__button[href*="edit"]');
+
+  if (editButton && editButton.parentNode) {
+    editButton.insertAdjacentElement("beforebegin", feedbackLink);
+
+    editButton.setAttribute("target", "_blank");
+    editButton.setAttribute("rel", "noopener");
+  }
+});

docs/mkdocs/stylesheets/extra.css

@@ -71,3 +71,40 @@ body[data-md-color-scheme="slate"] .md-nav__item--section > label.md-nav__link .
   -webkit-mask-image: var(--md-admonition-icon--important);
           mask-image: var(--md-admonition-icon--important);
 }
+
+/* Make label fully visible on hover */
+.md-content__button[href*="edit"]:hover::after {
+  opacity: 1;
+}
+
+/* Hide edit button on generated docs/examples pages */
+@media (min-width: 960px) {
+  .md-content__button[href*="docs/examples/"] {
+    display: none !important;
+  }
+}
+
+.md-content__button-wrapper {
+  position: absolute;
+  top: 0.6rem;
+  right: 0.8rem;
+  display: flex;
+  flex-direction: row;
+  align-items: center;
+  gap: 0.4rem;
+  z-index: 1;
+}
+
+.md-content__button-wrapper a {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  height: 24px;
+  width: 24px;
+  color: var(--md-default-fg-color);
+  text-decoration: none;
+}
+
+.md-content__button-wrapper a:hover {
+  color: var(--md-accent-fg-color);
+}

mkdocs.yaml

 site_name: vLLM
 site_url: https://docs.vllm.ai
 repo_url: https://github.com/vllm-project/vllm
+edit_uri: edit/main/docs/
 exclude_docs: |
   *.inc.md
   *.template.md
@@ -29,6 +30,7 @@ theme:
         icon: material/brightness-2
         name: Switch to system preference
   features:
+    - content.action.edit
     - content.code.copy
     - content.tabs.link
     - navigation.tracking
@@ -124,6 +126,7 @@ extra_css:
 extra_javascript:
   - mkdocs/javascript/run_llm_widget.js
   - https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_HTML
+  - mkdocs/javascript/edit_and_feedback.js
 
 # Makes the url format end in .html rather than act as a dir
 # So index.md generates as index.html and is available under URL /index.html