The twitter rules and policies now include the following paragraph:
We recognise that if people experience abuse on Twitter, it can jeopardize their ability to express themselves. Research has shown that some groups of people are disproportionately targeted with abuse online. This includes; women, people of color, lesbian, gay, bisexual, transgender, queer, intersex, asexual individuals, marginalized and historically underrepresented communities. For those who identity with multiple underrepresented groups, abuse may be more common, more severe in nature and have a higher impact on those targeted.
They add:
We prohibit targeting individuals with repeated slurs, tropes or other content that intends to dehumanize, degrade or reinforce negative or harmful stereotypes about a protected category. This includes targeted misgendering or deadnaming of transgender individuals.