cairo: Make sure we always push a transparency group in setSoftMaskFromImageMask()

Because that's what unsetSoftMaskFromImageMask() assumes.

https://bugs.freedesktop.org/show_bug.cgi?id=81624
annots: Fix a crash when adding annot without contents

Having no content in an annotation results in a crash when generating
its appearance, since the contents pointer is dereferenced.
For consistency, the same has been done in Annot::initialize.
glib: Return NULL in poppler_annot_get_contents also for empty strings
glib: Fix a memory leak when getting text layout and attributes
Don't check for inlineImg twice

Bug #82059
Improve non-latin characters in inline notes

Preview commit had by mistake changes in these two files that belong here

Bug #65956
Merge remote-tracking branch 'origin/poppler-0.26'
glib-demo: Remove use of deprecated gtk_dialog_get_action_area()

https://bugs.freedesktop.org/show_bug.cgi?id=82385
glib-demo: Replace use of deprecated gtk stock items

https://bugs.freedesktop.org/show_bug.cgi?id=82384
Makefile.am cleanups

Bug #79411
poppler: use poppler-data pkg-config for both cmake and autotools builds
core: Expose AnnotFreeText::parseAppearanceString

The frontends need to parse the DA string of the free text annotations
to get the font size and color of the text. This function is made public
to avoid the repeated effort.
glib: Add PopplerFontDescription boxed type

This boxed type is used to represent the font attributes of annotations.
glib: Extend FreeText annotation support

This patch allows adding new freetext annotations, their intent,
quadding and callout lines.
glib-demo: Extend demo for FreeText annotations

Adds font color, font size, intent properties of freetext annotations.
Also allows adding new free text annotations.
glib: Add PopplerAnnotBorder boxed type

This type is used to wrap the AnnotBorder class in the core to represent
border of annotations.
glib: Add border to annotations
glib-demo: Add border to free text annots
glib-demo freetext fix
fixup! glib-demo: Add border to free text annots