fn merge_reference(
references: &mut Vec<ResolvedSpellReference>,
spell: SpellIdx,
usage: SpellReferenceUsage,
projection_usage: SpellProjectionUsage,
)fn merge_reference(
references: &mut Vec<ResolvedSpellReference>,
spell: SpellIdx,
usage: SpellReferenceUsage,
projection_usage: SpellProjectionUsage,
)