download: Add a note about VC++ 2015 (fixes zealdocs/zeal#936)

Author: trollixx

download.html

@@ -9,6 +9,11 @@
 <div class="zd-section">
   <h2 id="windows">Windows</h2>
 
+  <div class="alert alert-info" role="alert">
+    If Zeal crashes on start, with or without a warning about missing <strong>vcruntime140.dll</strong>, please install
+    <a href="https://www.microsoft.com/en-us/download/details.aspx?id=52685"><strong>Microsoft Visual C++ 2015 Redistributable</strong></a>.
+  </div>
+
   <h3>Installer (MSI)</h3>
   <p>Use this installer to conveniently install Zeal as any other app.</p>
   <p>
@@ -44,6 +49,8 @@ <h3>Scoop</h3>
   <pre>&gt; scoop bucket add extras</pre>
   <p>To install Zeal run the following command:</p>
   <pre>&gt; scoop install zeal</pre>
+  <p>Scoop can also install Visual C++ 2015 Redistributable:</p>
+  <pre>&gt; scoop install vcredist2015</pre>
 
   <h3>CI builds</h3>
   <p>