gir: Clean up most warnings

Now remaining

../src/fr-process.h:77: Warning: FileRoller: fr_process_set_begin_func: argument func: Missing (scope) annotation for callback without GDestroyNotify (valid: call, async, forever)
../src/fr-process.h:80: Warning: FileRoller: fr_process_set_end_func: argument func: Missing (scope) annotation for callback without GDestroyNotify (valid: call, async, forever)
../src/fr-process.h:83: Warning: FileRoller: fr_process_set_continue_func: argument func: Missing (scope) annotation for callback without GDestroyNotify (valid: call, async, forever)
../src/fr-process.h:97: Warning: FileRoller: fr_process_set_out_line_func: argument func: Missing (scope) annotation for callback without GDestroyNotify (valid: call, async, forever)
../src/fr-process.h:100: Warning: FileRoller: fr_process_set_err_line_func: argument func: Missing (scope) annotation for callback without GDestroyNotify (valid: call, async, forever)

But I am not sure which (scope) to choose: The methods are setters, which are not really close to any of the examples in the docs. call probably is not it since the callback should be valid after the setter call ends, notified sounds reasonable since it will not make sense beyond the lifetime of the object but there is not a GDestroyNotify argument. Maybe async? But I am not certain the function can only be called once.