'command to jump to the file at a specified line and column
if this raises a NotImplementedError, we will fallback to
invoking view_file
:params:
pdf_file - full path to the generated pdf
tex_file - full path to the tex file of the active view
line - indicates the line number in the tex file (1-based)
col - incidates the column number in the tex file (1-based)
**kwargs:
keep_focus - if true, focus should return to ST'

def forward_sync(self, pdf_file, tex_file, line, col, **kwargs):

    raise NotImplementedError()
