Add: Silicon Gender Preference (#90879)

## About The Pull Request

This PR adds a secondary character preference which allows you to pick
gender for silicon characters, and have the option of matching or
separating that with their character's main gender. Silicon gender is
displayed in their examine text as expected.

## Why It's Good For The Game

People will have a way to identify the gender of their characters when
playing as a cyborg and AI!

## Changelog

🆑 A.C.M.O.
add: Adds an option for picking silicon gender to secondary character
preferences. Matches the main gender preference by default.
add: Adds gender pronouns in cyborg/AI examine text.
/🆑

code/modules/client/preferences/silicon_gender.dm

@@ -0,0 +1,37 @@
+#define SILICON_MALE "He/Him"
+#define SILICON_FEMALE "She/Her"
+#define SILICON_PLURAL "They/Them"
+#define SILICON_NEUTER "It/Its"
+
+/datum/preference/choiced/silicon_gender
+	category = PREFERENCE_CATEGORY_NON_CONTEXTUAL
+	savefile_identifier = PREFERENCE_CHARACTER
+	savefile_key = "silicon_gender"
+	var/static/use_character_gender = "Use character gender"
+	///Used to convert the read value of this preference into a gender
+	var/static/list/pronouns_to_genders = list(
+		"[SILICON_MALE]" = MALE,
+		"[SILICON_FEMALE]" = FEMALE,
+		"[SILICON_PLURAL]" = PLURAL,
+		"[SILICON_NEUTER]" = NEUTER,
+	)
+
+/datum/preference/choiced/silicon_gender/init_possible_values()
+	return list(
+		use_character_gender,
+		SILICON_MALE,
+		SILICON_FEMALE,
+		SILICON_PLURAL,
+		SILICON_NEUTER,
+	)
+
+/datum/preference/choiced/silicon_gender/create_default_value()
+	return SILICON_NEUTER
+
+/datum/preference/choiced/silicon_gender/apply_to_human(mob/living/carbon/human/target, value)
+	return
+
+#undef SILICON_MALE
+#undef SILICON_FEMALE
+#undef SILICON_PLURAL
+#undef SILICON_NEUTER