Attempt to make plone.api importable to Sphinx

Author: stevepiercy

Makefile

@@ -226,9 +226,9 @@ livehtml: deps  ## Rebuild Sphinx documentation on changes, with live-reload in
 
 .PHONY: rtd-pr-preview
 rtd-pr-preview: bin/python  ## Build pull request preview on Read the Docs
-	git submodule init; \
-	git submodule update; \
-	pip install -e submodules/plone.api[test]; \
+	git submodule init
+	git submodule update
+	pip install -e submodules/plone.api[test]
 	ln -s ../submodules/volto/docs/source ./docs/volto
 	ln -s ../submodules/plone.restapi ./docs/plone.restapi
 	ln -s ../submodules/plone.api/docs ./docs/plone.api