Small improvement

app/src/main/java/eu/faircode/email/MessageHelper.java

@@ -911,7 +911,9 @@ public class MessageHelper {
                         tlevel++;
                         if (tlevel > level)
                             sb.append("<blockquote>");
-                        line = line.substring(2);
+                        line = line.substring(1);
+                        if (line.startsWith(" "))
+                            line = line.substring(1);
                     }
                     for (int i = 0; i < level - tlevel; i++)
                         sb.append("</blockquote>");