Ignoring GtkTextTag when printing

Now that Text Editor has spell checking integrated I needed a way to print without displaying tags such our “misspelled word” underline squiggles. So GtkSourceView 5.2 will include gtk_source_print_compositor_ignore_tag() to do the obvious thing.

Previously, If you wanted to do this, you had to remove all your tags and then print, only to restore them afterwards. This should be a lot more convenient for people writing various GtkSourceView-based text editors. Although, I’m suspect many of them weren’t even doing this correctly to begin with, hence this PSA.