Update doc Makefile (#4754)

docs/Makefile

-# Minimal makefile for Sphinx documentation
-#
+.PHONY: all
+all: en zh
 
-# You can set these variables from the command line.
-SPHINXOPTS    =
-SPHINXBUILD   = sphinx-build
-SOURCEDIR     = source
-BUILDDIR      = build
+.PHONY: en
+en:
+	## English ##
+	sphinx-build -T source build/html
 
-# Put it first so that "make" without argument is like "make help".
-help:
-	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+.PHONY: zh
+zh:
+	## Chinese ##
+	sphinx-build -T -D language=zh source build/html_zh
 
 # Build message catelogs for translation
+.PHONY: i18n
 i18n:
-	@$(SPHINXBUILD) -M getpartialtext "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
-	sphinx-intl update -p "$(BUILDDIR)/getpartialtext" -d "$(SOURCEDIR)/locales" -l zh
+	sphinx-build -b getpartialtext source build/i18n
+	sphinx-intl update -p build/i18n -d source/locales -l zh
 
-.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 $(SPHINXOPTS).
-%: Makefile
-	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+.PHONY: clean
+clean:
+	rm -rf build
+	rm -rf source/reference/_modules

pipelines/fast-test.yml

@@ -19,10 +19,6 @@ stages:
       parameters:
         platform: ubuntu-latest
 
-    - script: |
-        sudo apt-get install -y pandoc
-      displayName: Install pandoc
-
     - script: |
         cd docs
         rstcheck -r source \
@@ -33,30 +29,27 @@ stages:
 
     - script: |
         cd docs
-        make -e SPHINXOPTS="-W --keep-going -T -q" html
+        sphinx-build -W --keep-going -T -q source build/html
       displayName: Sphinx sanity check
 
     - script: |
         set -e
         cd docs
-        rm -rf build
         sudo apt-get install -y gettext
         python tools/translation_patch.py
-        make -e SPHINXOPTS="-W --keep-going -T -q -D language='zh'" html
+        sphinx-build -W --keep-going -T -q -D language=zh source build/html_zh
       displayName: Sphinx sanity check (Chinese)
 
     - script: |
         set -e
         cd docs
-        rm -rf build
         make i18n
         git diff --exit-code source/locales
       displayName: Translation up-to-date
 
     - script: |
         cd docs
-        rm -rf build
-        make -e SPHINXOPTS="-W -T -b linkcheck -q --keep-going" html
+        sphinx-build -b linkcheck -W --keep-going -T -q source build/linkcheck
       displayName: External links integrity check
 
   - job: python