build(striker-ui): relocate rule comment to pre-section

striker-ui/Makefile.am

@@ -102,13 +102,15 @@ EXTRA_DIST		= \
 
 htmldir			= $(localstatedir)/www/html
 
+# Note: the input file to the generate endpoint prefix step must exist in
+#       EXTRA_DIST.
+#
 build:
 	-@echo "Print working directory."
 	pwd
 	-@echo "Install node modules (dependencies) prior to building."
 	npm clean-install
 	-@echo "Generate endpoint prefix."
-	# Note: the input file must exist in EXTRA_DIST.
 	sed 's@=.*@=/cgi-bin@' <env.development >.env.local
 	-@echo "Build front-end project."
 	npm run build