Internal array functions are now implemented in upb/internal/array.c and declared in
upb/internal/array.h, which only has local visibility.
PiperOrigin-RevId: 458260144
The current field/function names for upb_Array are quite confusing.
We will fix them in two steps, this being the first step.
PiperOrigin-RevId: 456687224
Lots of changes but it's all just moving things around.
Backward-compatible stub #include's have been provided for now.
upb_Arena/upb_Status have been split out from upb/upb.?
upb_Array/upb_Map/upb_MessageValue have been split out from upb/collections.?
upb_ExtensionRegistry has been split out from upb/msg.?
upb/decode_internal.h is now upb/internal/decode.h
upb/mini_table_accessors_internal.h is now upb/internal/mini_table_accessors.h
upb/table_internal.h is now upb/internal/table.h
upb/upb_internal.h is now upb/internal/upb.h
PiperOrigin-RevId: 456297617