fix: incorrect link resolution for transclusion in root index file (#853)

Co-authored-by: Lauréline Nevin <laureline.nevin@unicaen.fr>

quartz/plugins/transformers/links.ts

@@ -8,6 +8,7 @@ import {
   simplifySlug,
   splitAnchor,
   transformLink,
+  joinSegments,
 } from "../../util/path"
 import path from "path"
 import { visit } from "unist-util-visit"
@@ -107,7 +108,7 @@ export const CrawlLinks: QuartzTransformerPlugin<Partial<Options> | undefined> =
 
                   // url.resolve is considered legacy
                   // WHATWG equivalent https://nodejs.dev/en/api/v18/url/#urlresolvefrom-to
-                  const url = new URL(dest, `https://base.com/${curSlug}`)
+                  const url = new URL(dest, joinSegments(`https://base.com/`, curSlug))
                   const canonicalDest = url.pathname
                   let [destCanonical, _destAnchor] = splitAnchor(canonicalDest)
                   if (destCanonical.endsWith("/")) {