Don't allow unsafe characters in URLs
Don't allow unsafe characters in URLs

Why:

 * asciidoc files has links like http://example.com[Example] which
   currently when parsed includes the [Example] section
 * This causes errors when parsing the url later on.

This change addreses the need by:

 * Add unsafe characters to the exclusin in the regular expression match
   See https://perishablepress.com/stop-using-unsafe-characters-in-urls/

aarongustafson/jekyll-webmention_io,aarongustafson/jekyll-webmention_io,aarongustafson/jekyll-webmention_io,aarongustafson/jekyll-webmention_io