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// Manage possible letters/symbol in the name of charater. Control character (0x00-0x1f) are never accepted. Possible values are:
// NOTE: Applies to character, party and guild names.
// 0: no restriction (default)
// 1: only letters/symbols in 'name_letters' option.
// 2: Letters/symbols in 'name_letters' option are forbidden. All others are possibles.
name_option: 1