ges/ges-pitivi-formatter.h not included by ges.h

This causes the Rust tests to currently fail because the .gir file lists the corresponding types but they don't end up being defined when includes ges/ges.h, which is the header that is listed in the .gir file.

tests/layout.c: In function 'main':
<command-line>: error: invalid application of 'sizeof' to incomplete type 'GESPitiviFormatter' {aka 'struct _GESPitiviFormatter'}
tests/layout.c:10:31: note: in expansion of macro 'ABI_TYPE_NAME'
     printf("%zu\n%zu", sizeof(ABI_TYPE_NAME), alignof(ABI_TYPE_NAME));
                               ^~~~~~~~~~~~~
<command-line>: error: invalid application of '__alignof__' to incomplete type 'GESPitiviFormatter' {aka 'struct _GESPitiviFormatter'}
tests/layout.c:10:55: note: in expansion of macro 'ABI_TYPE_NAME'
     printf("%zu\n%zu", sizeof(ABI_TYPE_NAME), alignof(ABI_TYPE_NAME));
                                                       ^~~~~~~~~~~~~
tests/layout.c: In function 'main':
<command-line>: error: invalid application of 'sizeof' to incomplete type 'GESPitiviFormatterClass' {aka 'struct _GESPitiviFormatterClass'}
tests/layout.c:10:31: note: in expansion of macro 'ABI_TYPE_NAME'
     printf("%zu\n%zu", sizeof(ABI_TYPE_NAME), alignof(ABI_TYPE_NAME));
                               ^~~~~~~~~~~~~
<command-line>: error: invalid application of '__alignof__' to incomplete type 'GESPitiviFormatterClass' {aka 'struct _GESPitiviFormatterClass'}
tests/layout.c:10:55: note: in expansion of macro 'ABI_TYPE_NAME'
     printf("%zu\n%zu", sizeof(ABI_TYPE_NAME), alignof(ABI_TYPE_NAME));
                                                       ^~~~~~~~~~~~~