style-markdown

`semantic-line-breaks`: don't split footnotes

`semantic-line-breaks`: add line starting words to add line breaks for, too

remove `:` as punctuation for `footnotes-after-punctuation` since `[^N]: footnote` is mistakenly matched, too

add `--commit` flag to `git commit` the change, too

add semantic line breaks unit test using "The Future is Electric" snippet