2.1.0 wip - Corrected misprints in Using LESS page.

[ciembor]

I've corrected a couple of misprints on the Using LESS page. I also removed "code" tags surrounding static CSS values. To date only part of the content was formated this way.

[mdo]

Fixed the double @@ that you called out, but I'm leaving the code instances.

[ciembor]

So "code" tags should be also surrounding other CSS values (for example Georgia, "Times New Roman", Times, serif is in "code" and Menlo, Monaco, "Courier New", monospace is not). Wouldn't it be more consistent? Oh, and in this commit were also few other corrections:

inhereit -> inherit
ddd -> #ddd
51a351 -> #51a351