Skip frontmatter during Fountain parsing

[chuangcaleb]

Describe the task

When iterating thorough line-by-line,
if the first line is a triple-hyphen frontmatter opening,
then skip parsing until we hit the next triple-hyphen

Linked Issues

• BLOCKED BY: Return regex match from getLineFormat() to reuse in inline Deco.mark #6

Expected behavior

• When console.logging each line as it processes, the frontmatter lines should be exclued.

Screenshots

Additional context