Fix some commenting issues

src/main/java/app/model/languages/Java.java

@@ -48,7 +48,7 @@ public class Java implements ProgrammingLanguage {
       e("\\b[A-Z]\\w+\\b",            "identifier"),
       e("\\b(" + String.join("|", keywords) + ")\\b",
                                       "keyword"),
-      e("(?://.*)|(?:\\/?\\s?\\*.*)", "comment")
+      e("(?://.*)|/\\*(?:\\n|.)*\\*/", "comment")
     );
 
   public String getName() {

src/main/java/app/model/languages/Markdown.java

@@ -21,6 +21,7 @@ public class Markdown implements ProgrammingLanguage {
 
   private static final Map<Pattern, String> pattern = 
     Map.ofEntries(
+      e("<!--(?:.|\n)*-->", "comment"),
       e("##### .*", "ssssheader"),
       e("#### .*", "sssheader"),
       e("### .*", "ssheader"),