seralizer: Fix wrong order of unittest/docu
seralizer: Fix wrong order of unittest/docu

The documentation for `isStringSerializable` / `isPolicySerializable` is generated from the unittests.
The unittests are however in the wrong order, so that the docu for `isStringSerializable` is found where 
one would expect to see `isPolicySerializable` and vice versa.
DBankov/vibe.d,etcimon/vibe.d,Geod24/vibe.d,etcimon/vibe.d,rejectedsoftware/vibe.d,gedaiu/vibe.d,chalucha/vibe.d,AndreyMZ/vibe.d