Hello,

I have a small patch for `org-preview-latex-process-alist' making
the default setting for LaTeX source block evaluation be running
latex three times (instead of the current one). It is sometimes
necessary to run latex more than once to produce the final
document, a phenomenom described in the docstring for
`org-latex-pdf-process' which itself runs latex three times by
default. This patch just brings the former variable into parity
with the latter.