There's basicly two different sets of pages. One for the web wiki with tables and images and all the shiny formatting and one for the ingame help (the what's this links). The ingame help does not support any of the wiki or html markup. It's just plain text, about the same as you'd see in the edit window here.
All the ingame help pages use prefixes like Skill:, Item: or Terrain: to name a few. Duplicates like [[Item:File]] and [[File]] are not by accident but by design to create two pages with different formatting.
When creating pages or setting redirects you should check if the page is for the ingame help (Item:File) or the web wiki (File) and format or like he page accordingly.