markdown.sh doesn't warn about exceeding 80 characters in some cases

[m-iwanicki]

markdown.sh doesn't warn about line exceeding 80 characters if last word starts before 80 character limit.

Example:

miwanicki in ~/Documents λ cat tmp.md
# Title

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbb
miwanicki in ~/Documents λ markdown.sh check tmp.md
miwanicki in ~/Documents λ