Use highlight.js instead of prettify for syntax coloring

Originally based from work by @dotandimet.

Additional changes:

* highlight.js: Update to latest (10.3.1)

Install custom build limiting highlights for diff, plaintext, makefile,
bash, html/xml, sql, css, and perl only, to reduce from the normal
common pack size (100k to just 40k.)

This also adds the Mojolicious language plugin for highlight.js.

* debug.html.ep: Simplifiy highlight.js loading

Follow https://highlightjs.org/usage for this case, it seems more
reliable to let it highlight as well as determine the language to
be highlighted on its own.

* highlight-mojo-dark.css: Remake based on newer upstream dark theme

* Drop highligh-mojo-light.css

No longer needed here.

* Mojolicious.pm: Add license section for highlight.js

* Remove prettify.js

highlight.js now replaces it.  Thanks for the service, prettify.js!

lib/Mojolicious.pm

@@ -744,11 +744,11 @@ Licensed under the CC-SA License, Version 4.0 L<http://creativecommons.org/licen
 
 Licensed under the MIT License, L<http://creativecommons.org/licenses/MIT>.
 
-=head2 prettify.js
+=head2 highlight.js
 
-  Copyright (C) 2006, 2013 Google Inc..
+  Copyright (C) 2006, Ivan Sagalaev.
 
-Licensed under the Apache License, Version 2.0 L<http://www.apache.org/licenses/LICENSE-2.0>.
+Licensed under the BSD License, L<https://github.com/highlightjs/highlight.js/blob/master/LICENSE>.
 
 =head1 CODE NAMES
 

lib/Mojolicious/resources/public/mojo/highlight.js/highlight-mojo-dark.css

@@ -0,0 +1,56 @@
+.hljs {
+  display: block;
+  overflow-x: auto;
+}
+
+.hljs-keyword,
+.hljs-selector-tag,
+.hljs-literal,
+.hljs-section,
+.hljs-link {
+  color:#fcf0a4;
+}
+
+.hljs,
+.hljs-subst {
+  color:#889dbc;
+}
+
+.hljs-string,
+.hljs-title,
+.hljs-name,
+.hljs-type,
+.hljs-attribute,
+.hljs-symbol,
+.hljs-bullet,
+.hljs-built_in,
+.hljs-addition,
+.hljs-variable,
+.hljs-template-tag,
+.hljs-template-variable {
+  color: #9daa7e;
+}
+
+.hljs-comment,
+.hljs-quote,
+.hljs-deletion,
+.hljs-meta {
+  color:#726d73;
+}
+
+.hljs-keyword,
+.hljs-selector-tag,
+.hljs-literal,
+.hljs-title,
+.hljs-section,
+.hljs-doctag,
+.hljs-type,
+.hljs-name,
+.hljs-strong {
+  font-weight: bold;
+  color:#d5b57c;
+}
+
+.hljs-emphasis {
+  font-style: italic;
+}

lib/Mojolicious/resources/templates/mojo/debug.html.ep

@@ -7,8 +7,12 @@
     <meta http-equiv="Pragma" content="no-cache">
     <meta http-equiv="Expires" content="-1">
     %= javascript '/mojo/jquery/jquery.js'
-    %= javascript '/mojo/prettify/run_prettify.js'
-    %= stylesheet '/mojo/prettify/prettify-mojo-dark.css'
+    %= javascript '/mojo/highlight.js/highlight.min.js'
+    %= javascript '/mojo/highlight.js/mojolicious.min.js'
+    %= stylesheet '/mojo/highlight.js/highlight-mojo-dark.css'
+    <script>
+      hljs.initHighlightingOnLoad();
+    </script>
     <style>
       a img {
         border: 0;
@@ -263,7 +267,7 @@
           %= tag 'tr', $i ? (class => 'important') : (), begin
             <td class="key"><%= $key %></td>
             <td class="value wide">
-              <pre><code class="prettyprint"><%= $value %></code></pre>
+              <pre><code><%= $value %></code></pre>
             </td>
           % end
         % end

t/mojolicious/exception_lite_app.t

@@ -292,8 +292,9 @@ subtest 'Reuse exception' => sub {
 subtest 'Bundled static files' => sub {
   $t->get_ok('/mojo/jquery/jquery.js')->status_is(200)->content_type_is('application/javascript');
 
-  $t->get_ok('/mojo/prettify/run_prettify.js')->status_is(200)->content_type_is('application/javascript');
-  $t->get_ok('/mojo/prettify/prettify-mojo-dark.css')->status_is(200)->content_type_is('text/css');
+  $t->get_ok('/mojo/highlight.js/highlight.min.js')->status_is(200)->content_type_is('application/javascript');
+  $t->get_ok('/mojo/highlight.js/mojolicious.min.js')->status_is(200)->content_type_is('application/javascript');
+  $t->get_ok('/mojo/highlight.js/highlight-mojo-dark.css')->status_is(200)->content_type_is('text/css');
 
   $t->get_ok('/mojo/failraptor.png')->status_is(200)->content_type_is('image/png');
   $t->get_ok('/mojo/logo.png')->status_is(200)->content_type_is('image/png');