Added D.C., switched to full state names, and changed Prettier language to node

[AdamFinkle]

Closes #768

The issue commit

This pull request adds the District of Columbia to the list of available states (though it is not technically a state) and changes the labels of the states in the dropdown to their full names rather than their abbreviations. I have not added Puerto Rico, though it could be added in principle, because the issue did not mention it.

The Prettier commit

While addressing this issue, I encountered trouble running Prettier, but, per LLM suggestion, I changed the language of the hook from system to node, which fixed the problem. Why did this problem occur at all to begin with? According to the LLM, when Node is installed via tools like NVM, the Node that Prettier needs is hidden rather than being on the $PATH, which is where Prettier looks when the language is set to system. I don't know why this problem wasn't encountered by someone else earlier, but I encountered it. The LLM continued that the fix is to set the language to node; per the pre-commit documentation (https://pre-commit.com/)

node hooks work without any system-level dependencies.

The LLM concluded that this change enables Prettier to find node, even though we install it with NVM.

[Sarang-Patel]

Hi, This is good.

But the original issue wanted this implemented on the sign up page. But this change on cases is also needed so, keep the change on cases page and, if we can get this on sign up as well, it will be great.

Sign up page has its own dropdown, it can be replaced with this custom one.