Add check for usage of "here" in links

[georgik]

When writing a text with hyperlink, it's necessary to provide a reasonable text so that the reader knows what to expect when clicking on the link. Using word "here" in link is not sufficient.
Authors have tendency to overuse "here" and often there are multiple "here's" in the file, which leads to lower quality of the text.

Please, add PR and update the Contribution guide.