Limit the maximum width to 100 characters in the HTML list.

To make reading on wide screens easier.

src/generators/html.cpp

@@ -51,6 +51,10 @@ void write_html(ostream &out, const vector<entry_type> &entries)
     <meta charset="utf-8">
     <meta name="robots" content="noindex, nofollow">
     <style>
+      body
+      {
+        max-width: 100ch;
+      }
       .small
       {
         font-size: small;