Support for redirects other than the old site ones.

Uses this to provide redirects required by
pantsbuild/pants#20544

docusaurus.config.js

@@ -1,5 +1,6 @@
 import versions from "./versions.json";
-import redirects from "./old_site_redirects.js";
+import redirects from "./redirects.js";
+import old_site_redirects from "./old_site_redirects.js";
 import captionedCode from "./src/remark/captioned-code.js";
 import tabBlocks from "docusaurus-remark-plugin-tab-blocks";
 import fs from "fs";
@@ -369,7 +370,7 @@ const config = {
     [
       "@docusaurus/plugin-client-redirects",
       {
-        redirects,
+        redirects: old_site_redirects.concat(redirects),
       },
     ],
   ],

redirects.js

@@ -0,0 +1,10 @@
+export default [
+  {
+    from: "/2.19/docs/java-and-scala",
+    to: "/2.19/docs/jvm/java-and-scala",
+  },
+  {
+    from: "/2.19/docs/java-and-scala/kotlin",
+    to: "/2.19/docs/jvm/kotlin",
+  },
+];