Ending code blocks with a newline

The code block extraction was not resulting in a newline at the end
of each code block. This caused a number of false positive
failures. This commit changes code block extraction to end code
blocks with a newline.

Author: davidalber

tests/system.rs

@@ -548,6 +548,9 @@ fn get_code_blocks() -> Vec<CodeBlock> {
             // We've reached the end of the code block.
             extracting_block = false;
 
+            // Get a trailing newline in the code block.
+            code_block.push(String::new());
+
             // Store the code block information.
             code_blocks.push(CodeBlock {
                 config: ConfigPair {