Fix TOC filename issue on windows (fixes #39)
Fix TOC filename issue on windows (fixes #39)

Forgot in previous commit that windows root names start with '[A-Z]:'
and not '/'.

Aster89/vimtex,Aster89/vimtex,lervag/vimtex,kmarius/vimtex,lervag/vimtex,kmarius/vimtex