Investigate removing leading space in anchor links and placing the space before the hyperlink.

[evbacher]

See https://github.com/evbacher/gd2md-html/issues/185. This is not technically an error, as the link text in the Google Doc actually contains a leading space. But the Google Doc renders the link as the user probably intended, with the space outside the in front of the link, not as part of the link.

While this is user error, it may be common.

If we take care of leading spaces this way, we should also do the same for trailing spaces in links.