"E700: Unknown function: s:compile_to_html" while opening asciidoc files
While opening asciidoc files, error occurs:

```
Error detected while processing function SpaceVim#mapping#space#refrashLSPC[4]..<SNR>59_language_specified_mappings:
line    1:
E700: Unknown function: s:compile_to_html
E700: Unknown function: s:compile_to_html
```

After bisect, it first introduced in  ``88f95541221e6e5632ee157c68e1b8539d982bee``(Update lang#asciidoc layer (#3556)
).  The following code binds ``[SPC] l h`` to ``s:compile_tohtml``, but such function is not exists.

```vim
function! s:language_specified_mappings() abort
  call SpaceVim#mapping#space#langSPC('nmap', ['l','h'],
        \ 'call call('
        \ . string(function('s:compile_to_html')) . ', [])',
        \ 'compile-to-html', 1)
endfunction
```