Accept digits in "Link Defaults" spec names.

"HTML5" currently doesn't match the "Link Defaults" regex. This patch
fixes that oversight.
Merge pull request #147 from mikewest/html5

Accept digits in "Link Defaults" spec names.
Unfix typography for autolinking.

"the script block's source" can't be autolinked, as the single quote is
typographized into a curly quote before autolinking. This patch unfixes
the typography before passing the string into 'getRef'.
Unfix typography before creating local definition text.