Better wrapping of long URLs immediately following short words

[jlevy]

When a long URL is adjacent to a small text word, we don't wrap optimally. Mainly comes up with parentheses and the like.

Example: https://github.com/jlevy/atom-flowmark/commit/92ae1c043c5245d4b922506518f5805b20f26d8e#diff-45486205dce63c55188d5aa2d93c4877R170

(The issue is our current approach only looks forward, and this requires "looking back" and breaking the line earlier.)