[gjs] (16 commits) ...Merge branch 'annotate-return-values' into 'master'

[Philip Chimento <pchimento src gnome org>]

Summary of changes:

  0dc9ffa... console: Make print_single_error() infallible
  4ce4a04... foreign: Make gjs_struct_foreign_register() infallible
  ba32a07... object: Make gjs_object_associate_closure() infallible
  5aa46c2... js: Fix missing error checks
  8a29daa... js: Fix various error handling mistakes
  f8672ea... js: Mark places where error checking is not necessary
  425b94d... js: Introduce annotations for using return values
  d69605e... boxed, gerror: Make define_class() functions fallible
  ee7dc86... gobject: Make jsobj_set_gproperty() fallible
  cf857bc... object: Make ObjectPrototype constructor fallible
  e3b2143... importer: Make load_module_elements() fallible
  221ffc1... gtype: Fix error handling in gjs_gtype_get_actual_gtype()
  ed523c6... jsapi-util: Fix error handling in gjs_get_string_id()
  60f9a1e... importer: Fix error handling in load_module_init()
  7f254f3... arg: Various style improvements
  dcb26e6... Merge branch 'annotate-return-values' into 'master'