This reverts commit 833666d462.
The _pdb files are an implementation detail and we do not want
separate doc sections for them, the conflicts need so be resolved in
another way.
Otherwise we get a few duplicate sections since some of the non-PDB
files are named similarly.
Fix this GObject introspection warning and other similar warnings:
> libgimp/gimp_pdb.c:28: Warning: Gimp: multiple comment blocks
> documenting 'SECTION:gimp:' identifier (already seen at gimp.c:129).
All foo_pdb.c functions in libgimp regenerated. I have reviewed this a
dozen times, but please have a look, there might well be glitches and
our public API is sortof important...
