The wording is not completely incorrect: If you search for a word that has an according page in the wiki, the button says "Edit this page" indeed!
There should be either a mechanism that chooses the right wording or that sentence should be entirely omitted.
Keep in mind that the button could either say "Create this page", or "Edit this page" or even "Show pagesource" (as stated already in FS#233
), e.g. http://wiki.splitbrain.org/?do=search&id=start