bpo-38862: IDLE Strip Trailing Whitespace fixes end newlines  (GH-17366)

Extra newlines are removed at the end of non-shell files. If the file only has newlines after stripping other trailing whitespace, all are removed, as is done by patchcheck.py.
diff --git a/Lib/idlelib/help.html b/Lib/idlelib/help.html
index 0754f24..09dc4c5 100644
--- a/Lib/idlelib/help.html
+++ b/Lib/idlelib/help.html
@@ -4,7 +4,7 @@
 <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
     <meta charset="utf-8" />
-    <title>IDLE &#8212; Python 3.9.0a0 documentation</title>
+    <title>IDLE &#8212; Python 3.9.0a1 documentation</title>
     <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" />
     <link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
 
@@ -17,14 +17,14 @@
     <script type="text/javascript" src="../_static/sidebar.js"></script>
 
     <link rel="search" type="application/opensearchdescription+xml"
-          title="Search within Python 3.9.0a0 documentation"
+          title="Search within Python 3.9.0a1 documentation"
           href="../_static/opensearch.xml"/>
     <link rel="author" title="About these documents" href="../about.html" />
     <link rel="index" title="Index" href="../genindex.html" />
     <link rel="search" title="Search" href="../search.html" />
     <link rel="copyright" title="Copyright" href="../copyright.html" />
     <link rel="next" title="Other Graphical User Interface Packages" href="othergui.html" />
-    <link rel="prev" title="tkinter.scrolledtext — Scrolled Text Widget" href="tkinter.scrolledtext.html" />
+    <link rel="prev" title="tkinter.tix — Extension widgets for Tk" href="tkinter.tix.html" />
     <link rel="canonical" href="https://docs.python.org/3/library/idle.html" />
 
 
@@ -62,7 +62,7 @@
           <a href="othergui.html" title="Other Graphical User Interface Packages"
              accesskey="N">next</a> |</li>
         <li class="right" >
-          <a href="tkinter.scrolledtext.html" title="tkinter.scrolledtext — Scrolled Text Widget"
+          <a href="tkinter.tix.html" title="tkinter.tix — Extension widgets for Tk"
              accesskey="P">previous</a> |</li>
 
     <li><img src="../_static/py.png" alt=""
@@ -71,7 +71,7 @@
 
 
     <li>
-      <a href="../index.html">3.9.0a0 Documentation</a> &#187;
+      <a href="../index.html">3.9.0a1 Documentation</a> &#187;
     </li>
 
           <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
@@ -240,7 +240,8 @@
 </dd>
 <dt>Strip trailing whitespace</dt><dd><p>Remove trailing space and other whitespace characters after the last
 non-whitespace character of a line by applying str.rstrip to each line,
-including lines within multiline strings.</p>
+including lines within multiline strings.  Except for Shell windows,
+remove extra newlines at the end of the file.</p>
 </dd>
 </dl>
 </div>
@@ -886,8 +887,8 @@
 </ul>
 
   <h4>Previous topic</h4>
-  <p class="topless"><a href="tkinter.scrolledtext.html"
-                        title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">tkinter.scrolledtext</span></code> — Scrolled Text Widget</a></p>
+  <p class="topless"><a href="tkinter.tix.html"
+                        title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">tkinter.tix</span></code> — Extension widgets for Tk</a></p>
   <h4>Next topic</h4>
   <p class="topless"><a href="othergui.html"
                         title="next chapter">Other Graphical User Interface Packages</a></p>
@@ -919,7 +920,7 @@
           <a href="othergui.html" title="Other Graphical User Interface Packages"
              >next</a> |</li>
         <li class="right" >
-          <a href="tkinter.scrolledtext.html" title="tkinter.scrolledtext — Scrolled Text Widget"
+          <a href="tkinter.tix.html" title="tkinter.tix — Extension widgets for Tk"
              >previous</a> |</li>
 
     <li><img src="../_static/py.png" alt=""
@@ -928,7 +929,7 @@
 
 
     <li>
-      <a href="../index.html">3.9.0a0 Documentation</a> &#187;
+      <a href="../index.html">3.9.0a1 Documentation</a> &#187;
     </li>
 
           <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
@@ -959,11 +960,11 @@
 <br />
     <br />
 
-    Last updated on Sep 01, 2019.
+    Last updated on Nov 24, 2019.
     <a href="https://docs.python.org/3/bugs.html">Found a bug</a>?
     <br />
 
-    Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 2.1.2.
+    Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 2.1.1.
     </div>
 
   </body>