g_irepository_dump: Update doc to match code

The input file no longer only consists of names of get_type-functions,
instead begins with either "get-type:" or "error-quark:".

https://bugzilla.gnome.org/show_bug.cgi?id=701639
Fix indentation on pretty printed Makefile rules

https://bugzilla.gnome.org/show_bug.cgi?id=701679