app, devel-docs, libgimp: updating gimp_text_layer_[gs]et_font() and new…

… function gimp_font_get_pango_font_description().

Also updating file-pdf-save which is the only plug-in using these right now.

Note that I am not fully happy with the new function
gimp_font_get_pango_font_description() because I experienced some weird behavior
in file-pdf-save which is that some fonts were wrong if this is called after
pango_cairo_font_map_set_resolution().
But let's say this is a first step looking for improvements.

devel-docs/reference/gimp/gimp-3.0.toml.in

@@ -61,6 +61,11 @@ search_index = true
   description = "A 2D graphics library with support for multiple output devices"
   docs_url = "https://www.cairographics.org/manual/"
 
+  [dependencies."Pango-1.0"]
+  name = "Pango"
+  description = "Internationalized text layout and rendering"
+  docs_url = "https://docs.gtk.org/Pango/"
+
 [theme]
 name = "basic"
 show_index_summary = true

devel-docs/reference/gimp/urlmap.js

@@ -8,4 +8,5 @@ baseURLs = [
   [ 'GdkPixbuf', 'https://docs.gtk.org/gdk-pixbuf/' ],
   [ 'Gio',       'https://docs.gtk.org/gio/' ],
   [ 'Gtk',       'https://docs.gtk.org/gtk3/' ],
+  [ 'Pango',     'https://docs.gtk.org/Pango/' ],
 ]