Wiki links to heading containing non-ascii symbols don't work (BB-9059)

Links to heading in wiki don't work when heading contains some special or not ascii characters.

I have headings with russian symbols in them, and they have id attributes on a rendered wiki page id="!", so links of type

[[wiki_page#heading_containing_russian_chars]]

don't work.

Also there is another problem about links to page headings. It looks like links to the same page

[[#heading name]]

also don't work. On a rendered wiki page they have url :

/bb-account/project/wiki/#heading name.

Please tell me if you need to view an example wiki with described problems.

Thank you!