Log Message:
vala: update to 0.52.3.

Vala 0.52.3
===========
 * Various improvements and bug fixes:
  - codegen:
    + Apply gconstpointer to gpointer cast to GenericType only
    + Fix access to captured generics in async method of interfaces (2)
    + Use if-clause for is_in_destructor() condition to be more clear
    + Add missing "_return" label and "_inner_error*_" \ 
declaration in dtors
    + Don't use G_GNUC_INTERNAL on implicit type specific fields
  - vala:
    + length-type of arrays must not be nullable
    + Report a warning for unhandled errors in destructors
  - parser:
    + Minor semantic checks to improve error messages
    + Allow empty member-initializer and accept trailing comma
    + Include INTERR token in source_reference of parsed types