Improve wiki linking

wikilinks.go

@@ -115,13 +115,14 @@ func wikiTargetHref(target string) string {
 	return b.String()
 }
 
-// wikiTargetExists reports whether the on-disk folder backing the target
-// exists under root.
+// wikiTargetExists reports whether the on-disk path backing the target exists
+// under root. Any existing path — file or folder — counts as resolved; only a
+// missing path is treated as broken.
 func wikiTargetExists(root, target string) bool {
 	target = normalizeWikiTarget(target)
 	fsPath := filepath.Join(root, filepath.FromSlash(strings.TrimPrefix(target, "/")))
-	info, err := os.Stat(fsPath)
-	return err == nil && info.IsDir()
+	_, err := os.Stat(fsPath)
+	return err == nil
 }
 
 // wikiDefaultDisplay returns the last segment of a target, or "/" for the root.