“invert” is the proper word

Signed-off-by: Chris “Kwpolska” Warrick <kwpolska@gmail.com>
Fix #1076 -- remove double negative settings (invert HIDE_* into SHOW_*).

new                     =     old                     = default
SHOW_SOURCELINK         = not HIDE_SOURCELINK         = True
SHOW_UNTRANSLATED_POSTS = not HIDE_UNTRANSLATED_POSTS = True

Signed-off-by: Chris “Kwpolska” Warrick <kwpolska@gmail.com>