for now it tests only syntax of bash code starts with '$'

…method extract_code, add Array of results from testing bash syntax

and add comments.

Add comment, remove unnecessary parts of condition, deleting '\n' from code replace with an array of codelines without '\n' on start/end and whitespaces, rename variables, replace 'results' Array with Hash, change code structure to be easy readable

rename PAGES to MD_FILES and codespans to code_lines, change extract method, add file path into decsribe error message, replace 'each' with 'inject'