LibMarkdown: Add additional spacing for terminal rendering

This patch adds spacing to give a sense of structure to markdown
documents viewed in the terminal. This also makes the content easier
to read.

Userland/Libraries/LibMarkdown/CodeBlock.cpp

@@ -49,8 +49,11 @@ String CodeBlock::render_for_terminal(size_t) const
 {
     StringBuilder builder;
 
-    builder.append(m_code);
+    for (auto line : m_code.split('\n')) {
-    builder.append("\n\n");
+        builder.append("  ");
+        builder.append(line);
+        builder.append("\n");
+    }
 
     return builder.build();
 }

Userland/Libraries/LibMarkdown/List.cpp

@@ -45,12 +45,11 @@ String List::render_for_terminal(size_t) const
     for (auto& item : m_items) {
         builder.append("  ");
         if (m_is_ordered)
-            builder.appendff("{}. ", ++i);
+            builder.appendff("{}.", ++i);
         else
-            builder.append("* ");
+            builder.append("*");
         builder.append(item->render_for_terminal());
     }
-    builder.append("\n");
 
     return builder.build();
 }

Userland/Libraries/LibMarkdown/Paragraph.cpp

@@ -30,6 +30,7 @@ String Paragraph::render_to_html(bool tight) const
 String Paragraph::render_for_terminal(size_t) const
 {
     StringBuilder builder;
+    builder.append("  ");
     builder.append(m_text.render_for_terminal());
     builder.append("\n\n");
     return builder.build();

Userland/Libraries/LibMarkdown/Table.cpp

@@ -63,6 +63,8 @@ String Table::render_for_terminal(size_t view_width) const
         builder.append("\n");
     }
 
+    builder.append("\n");
+
     return builder.to_string();
 }