FIX adds alt property to preformated text in HTML

lib-htmgem.inc.php

@@ -314,7 +314,8 @@ class GemtextTranslate_html {
                 case "```":
                     $text = implode("\n", $node["texts"]);
                     self::htmlPrepare($text);
-                    $output .= "<pre>\n$text\n</pre>\n";
+                    $alt = $node["alt"];
+                    $output .= "<pre alt='$alt'>\n$text\n</pre>\n";
                     break;
                 case ">":
                     $output .= "<blockquote>\n";

tests/files_with_html/preformated-utf-16.gmi.html

@@ -1,13 +1,13 @@
-<pre>
+<pre alt='Text to not display but keep in memory'>
 Bellow here, an empty line
 
 </pre>
 <p>&nbsp;</p>
-<pre>
+<pre alt='X'>
 &nbsp;
 </pre>
 <p>&nbsp;</p>
-<pre>
+<pre alt=''>
 No
 alt
 text

tests/files_with_html/preformated.gmi.html

@@ -1,13 +1,13 @@
-<pre>
+<pre alt='Text to not display but keep in memory'>
 Bellow here, an empty line
 
 </pre>
 <p>&nbsp;</p>
-<pre>
+<pre alt='X'>
 &nbsp;
 </pre>
 <p>&nbsp;</p>
-<pre>
+<pre alt=''>
 No
 alt
 text

tests/files_with_html/text-utf-16.gmi.html

@@ -223,7 +223,7 @@
 <p>&nbsp;</p>
 <p>Lines beginning with the two characters &quot;=&gt;&quot; are link lines, which have the following syntax:</p>
 <p>&nbsp;</p>
-<pre>
+<pre alt=''>
 =&gt;[&lt;whitespace&gt;]&lt;URL&gt;[&lt;whitespace&gt;&lt;USER-FRIENDLY LINK NAME&gt;]
 </pre>
 <p>&nbsp;</p>
@@ -237,7 +237,7 @@
 <p>&nbsp;</p>
 <p>All the following examples are valid link lines:</p>
 <p>&nbsp;</p>
-<pre>
+<pre alt=''>
 =&gt; gemini://example.org/
 =&gt; gemini://example.org/ An example link
 =&gt; gemini://example.org/foo	Another example link at the same host

tests/files_with_html/text.gmi.html

@@ -223,7 +223,7 @@
 <p>&nbsp;</p>
 <p>Lines beginning with the two characters &quot;=&gt;&quot; are link lines, which have the following syntax:</p>
 <p>&nbsp;</p>
-<pre>
+<pre alt=''>
 =&gt;[&lt;whitespace&gt;]&lt;URL&gt;[&lt;whitespace&gt;&lt;USER-FRIENDLY LINK NAME&gt;]
 </pre>
 <p>&nbsp;</p>
@@ -237,7 +237,7 @@
 <p>&nbsp;</p>
 <p>All the following examples are valid link lines:</p>
 <p>&nbsp;</p>
-<pre>
+<pre alt=''>
 =&gt; gemini://example.org/
 =&gt; gemini://example.org/ An example link
 =&gt; gemini://example.org/foo	Another example link at the same host