fix #6583, fix #14376, index+search now generated for all projects, many bug fixes with nim doc (#14324)

* refs #6583 fix nim doc output
* changelog
* change default for outDir when unspecified
* cleanups
* --project implies --index

config/nimdoc.cfg

@@ -100,7 +100,7 @@ doc.body_toc = """
         <a href="lib.html">Standard library</a>
       </li>
       <li>
-        <a href="theindex.html">Index</a>
+        <a href="$theindexhref">Index</a>
       </li>
     </ul>
   </div>
@@ -143,7 +143,7 @@ doc.body_toc_group = """
         <a href="lib.html">Standard library</a>
       </li>
       <li>
-        <a href="theindex.html">Index</a>
+        <a href="$theindexhref">Index</a>
       </li>
     </ul>
   </div>
@@ -183,6 +183,9 @@ doc.body_toc_group = """
   </div>
   <div id="global-links">
     <ul class="simple">
+    <li>
+      <a href="$theindexhref">Index</a>
+    </li>
     </ul>
   </div>
   <div id="searchInputDiv">
@@ -239,7 +242,7 @@ doc.file = """<?xml version="1.0" encoding="utf-8" ?>
 <title>$title</title>
 <link rel="stylesheet" type="text/css" href="$nimdoccss">
 
-<script type="text/javascript" src="dochack.js"></script>
+<script type="text/javascript" src="$dochackjs"></script>
 
 <script type="text/javascript">
 function main() {