doc: promote make-mode build call

This variant of building is simpler; promote its use instead.

Signed-off-by: James Knight <[email protected]>

Author: jdknight

doc/tutorial.rst

@@ -140,9 +140,9 @@ building/publishing:
 
     make confluence
      (or)
-    sphinx-build -b confluence . _build/confluence -E -a
+    sphinx-build -M confluence . _build -E -a
      (or)
-    python -m sphinx -b confluence . _build/confluence -E -a
+    python -m sphinx -M confluence . _build -E -a
 
 Documentation of the project should now be published to the Confluence site.