remove some more sphinx leftovers

Author: isabelizimm

docs/Makefile

@@ -1,17 +1,8 @@
 # Minimal makefile for quartodoc documentation
-#
-
-# You can set these variables from the command line, and also
-# from the environment for the first two.
-SPHINXOPTS    ?=
-SPHINXBUILD   ?= sphinx-build
-SOURCEDIR     = source
-BUILDDIR      = _build
 
 .PHONY: help Makefile
 
-# Catch-all target: route all unknown targets to Sphinx using the new
-# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+# Catch-all target:
 %: Makefile
 	python -m quartodoc build
 	python -m quartodoc interlinks