Change faq reference from docs.jquery.com to learn.jquery.com when learn site goes live

[kswedberg]

The entries/id-selector.xml entry has a link to http://docs.jquery.com/Frequently_Asked_Questions#How_do_I_select_an_element_by_an_ID_that_has_characters_used_in_CSS_notation.3F. When the learn site goes live, that link should go to:

http://learn.jquery.com/faq/how_do_i_select_an_element_by_an_id_that_has_characters_used_in_css_notation/

[kswedberg]

The correct url is http://learn.jquery.com/faq/how-do-i-select-an-element-by-an-id-that-has-characters-used-in-css-notation/