[clean] Rename types ending in _t

• nlc::hash_t -> nlc::hash_result
• nlc::align_t -> nlc::alignment
• nlc::codepoint_t -> nlc::codepoint_type
• nlc::assert_callback_t -> nlc::assert_callback_type
• nlc::nullptr_t -> nlc::nullptr_type
• nlc::null_t -> nlc::null_type
• nlc::comparison_t -> nlc::comparison_result
• nlc::meta::if_t -> nlc::meta::if_cond
• nlc::time::time_t -> nlc::time::duration
• name##_t -> name##_dim (unit presets)
• internal types (radix_sort, match, variant, function, vector)