put the basewiki index and sandbox pages in a subdir of the doc wiki

[ikiwiki] / doc / bugs / wiki_links_still_processed_inside_code_blocks.mdwn

In [[markdown]] syntax, none of the other special characters get processed inside a code block.  However, in ikiwiki, [[wiki links|wikilink]] and [[preprocessor directives|preprocessordirective]] still get processed inside a code block, requiring additional escaping.  For example, `[links don't work](#here)`, but `a [[wikilink]] becomes HTML`.