docs: add discussions with giscus (#27172)

docs/src/theme/DocItem/Paginator/index.js

@@ -1,11 +1,25 @@
 import React from 'react';
 import Paginator from '@theme-original/DocItem/Paginator';
 import Feedback from "@theme/Feedback";
+import Giscus from "@giscus/react";
 
 export default function PaginatorWrapper(props) {
   return (
     <>
       <Feedback />
+      <Giscus
+        repo="langchain-ai/langchain"
+        repoId="R_kgDOIPDwlg"
+        category="Docs Discussions"
+        categoryId="DIC_kwDOIPDwls4CjJYb"
+        mapping="pathname"
+        strict="0"
+        reactionsEnabled="0"
+        emitMetadata="0"
+        inputPosition="bottom"
+        theme="preferred_color_scheme"
+        lang="en"
+        loading="lazy" />
       <Paginator {...props} />
     </>
   );

docs/src/theme/Feedback.js

@@ -220,10 +220,6 @@ export default function Feedback() {
     onMouseUp: (e) => (e.currentTarget.style.backgroundColor = "#f0f0f0"),
   };
 
-  const newGithubIssueURL = pathname
-    ? `https://github.com/langchain-ai/langchain/issues/new?assignees=&labels=03+-+Documentation&projects=&template=documentation.yml&title=DOC%3A+%3CIssue+related+to+${pathname}%3E&url=https://python.langchain.com${pathname}`
-    : "https://github.com/langchain-ai/langchain/issues/new?assignees=&labels=03+-+Documentation&projects=&template=documentation.yml&title=DOC%3A+%3CPlease+write+a+comprehensive+title+after+the+%27DOC%3A+%27+prefix%3E";
-
   return (
     <div style={{ display: "flex", flexDirection: "column" }}>
       <hr />
@@ -296,14 +292,6 @@ export default function Feedback() {
           </div>
         </>
       )}
-      <br />
-      <h4>
-        You can also leave detailed feedback{" "}
-        <a target="_blank" href={newGithubIssueURL}>
-          on GitHub
-        </a>
-        .
-      </h4>
     </div>
   );
 }