pub fn find_main_tex(dir: &Path) -> Result<PathBuf, String>Expand description
Discover the main .tex file inside dir, mirroring the binary’s
--whatsin=directory heuristic. The returned path is rooted at
dir. Errors carry a human-readable diagnostic on Fatal: failure
modes (PDF mis-named as TeX, only %auto-ignore files, no TeX at
all).