Minor textprop integer cleanup.

Minor textprop integer cleanup.

* intervals.h, textprop.c (add_text_properties_from_list):
Return void, not int, since nobody uses the return value.
* textprop.c (validate_plist, add_properties, remove_properties)
(Fadd_text_properties):
Don't assume list length fits in int.
(interval_has_all_properties, interval_has_some_properties)
(interval_has_some_properties_list, add_properties, remove_properties)
(Fadd_text_properties, Fremove_text_properties)
(Fremove_list_of_text_properties, text_property_stickiness):
Use bool for booleans.
(Fadd_text_properties, Fremove_text_properties):
(Fremove_list_of_text_properties):
Reindent do-while as per GNU style.