Fix gtk_file_chooser_error_stack_set_custom_error

This never worked, due to a typo.
10 jobs for matthiasc/for-master in 43 minutes and 46 seconds (queued for 1 second)
Status Job ID Name Coverage
  .Pre
failed #808279
allowed to fail
style-check-diff

00:00:50

 
  Build
passed #808280
fedora-x86_64

00:06:07

passed #808282
win32-ps
msys2-mingw64

00:03:00

passed #808281
release-build

00:06:29

 
  Analysis
failed #808284
privileged allowed to fail
asan-build

00:14:06

passed #808283
static-scan

00:28:38

 
  Docs
passed #808285
reference

00:07:48

 
  Flatpak
manual #808286
flatpak allowed to fail manual
flatpak-manual:demo
manual #808288
flatpak allowed to fail manual
flatpak-manual:icon-browser
manual #808287
flatpak allowed to fail manual
flatpak-manual:widget-factory
 
Name Stage Failure
failed
asan-build Analysis
Processing gtk suite css:
- css: 195 total, 194 pass, 1 fail
Processing gtk suite tools:
- tools: 3 total, 3 pass, 0 fail
Processing gtk suite reftest:
- reftest: 132 total, 130 pass, 2 fail
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1
failed
style-check-diff .Pre
 void
-gtk_file_chooser_widget_initial_focus (GtkFileChooserWidget *chooser);
+gtk_file_chooser_widget_initial_focus (GtkFileChooserWidget *chooser);

G_END_DECLS

Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1