Build: remove support for pdflatex

[humitos]

Our current code decides whether using pdflatex or latexmk depending on the Sphinx version. It uses pdflatex when sphinx<=1.6.x and for all the other versions it uses latexmk:

readthedocs.org/readthedocs/doc_builder/backends/sphinx.py

Lines 332 to 342 in 8195ecb

	command = [
	self.python_env.venv_bin(filename='python'),
	'-c',
	(
	'"'
	'import sys; '
	'import sphinx; '
	'sys.exit(0 if sphinx.version_info >= (1, 6, 1) else 1)'
	'"'
	),
	]

I think we could safely remove this chunk of code since nobody is using such an old version to build their documentation with Sphinx. This Metabase query shows that the oldest version currently used on Read the Docs is 1.8.6 ¹

Footnotes

1. this is because we are forcing pinning to that version for old projects ↩

[SyedMa3]

I can't find this chunk of code in the main branch. So assuming this code is removed, so issue can be closed? @humitos

[humitos]

Yes, we can close this issue. This was done in #9967. Thanks 👍🏼