fix: run linkify checks on entire parent tree
fix: run linkify checks on entire parent tree

A lot of web editors create elaborate DOM trees and it is not enough to
check if parent is safe for linkification.

This change walks back over entire parent tree to ensure none of parents
has a no-go flag for linkification (eg. HTMLElement.contentEditable property)

lidel/ipfs-firefox-addon,lidel/ipfs-firefox-addon,lidel/ipfs-firefox-addon