Add JOBS parameter to docs Makefile (GH-101395)

(cherry picked from commit 1a62ae8)

Co-authored-by: Christophe Nanteuil <35002064+christopheNan@users.noreply.github.com>

Doc/Makefile

@@ -8,6 +8,7 @@ PYTHON       = python3
 VENVDIR      = ./venv
 SPHINXBUILD  = PATH=$(VENVDIR)/bin:$$PATH sphinx-build
 BLURB        = PATH=$(VENVDIR)/bin:$$PATH blurb
+JOBS         = auto
 PAPER        =
 SOURCES      =
 DISTVERSION  = $(shell $(PYTHON) tools/extensions/patchlevel.py)
@@ -17,7 +18,7 @@ SPHINXERRORHANDLING = -W
 PAPEROPT_a4     = -D latex_elements.papersize=a4paper
 PAPEROPT_letter = -D latex_elements.papersize=letterpaper
 
-ALLSPHINXOPTS = -b $(BUILDER) -d build/doctrees $(PAPEROPT_$(PAPER)) -j auto \
+ALLSPHINXOPTS = -b $(BUILDER) -d build/doctrees $(PAPEROPT_$(PAPER)) -j $(JOBS) \
                 $(SPHINXOPTS) $(SPHINXERRORHANDLING) . build/$(BUILDER) $(SOURCES)
 
 .PHONY: help build html htmlhelp latex text texinfo changes linkcheck \