fix #16973 ; nim doc now shows correct, canonical import name in title (#16999)

* nim doc now shows correct import name in title

nimdoc/test_out_index_dot_html/expected/index.html

@@ -17,7 +17,7 @@
 <link href='https://fonts.googleapis.com/css?family=Source+Code+Pro:400,500,600' rel='stylesheet' type='text/css'/>
 
 <!-- CSS -->
-<title>foo</title>
+<title>nimdoc/test_out_index_dot_html/foo</title>
 <link rel="stylesheet" type="text/css" href="nimdoc.out.css">
 
 <script type="text/javascript" src="dochack.js"></script>
@@ -64,7 +64,7 @@ window.addEventListener('DOMContentLoaded', main);
 <body>
 <div class="document" id="documentId">
   <div class="container">
-    <h1 class="title">foo</h1>
+    <h1 class="title">nimdoc/test_out_index_dot_html/foo</h1>
     <div class="row">
   <div class="three columns">
   <div class="theme-switch-wrapper">