lang: add the InitSpace macro

[Aursen]

Adds a new macro to automatically calculate the space.

#[account]
#[derive(InitSpace)]
pub struct DataAccount {
    pub data: u64,
}

#[derive(Accounts)]
pub struct Initialize<'info> {
    #[account(mut)]
    pub payer: Signer<'info>,
    pub system_program: Program<'info, System>,
    #[account(init, payer=payer, space= 8 + DataAccount::INIT_SPACE)]
    pub data: Account<'info, DataAccount>,
}

What remains to be done is:

• Fix the naming and the other stuffs like this (if needed)
• Implement the macro directly in the account attribute
• Add some docs in the proc macro
• Fix the issue with max_len when the type is Vec<Vec<>>
• Fix examples

[vercel]

@Aursen is attempting to deploy a commit to the coral-xyz Team on Vercel.

A member of the Team first needs to authorize it.

[Aursen]

@Henry-E What do you want for the name of the macro? InitSpace, MaxSpace, Space or other?

[Henry-E]

The InitSpace name looks good for now, I will try to run these tests locally tomorrow and figure out the issue.

Aside from the failing tests, is the PR feature complete now in your opinion?

[Aursen]

Aside from the failing tests, is the PR feature complete now in your opinion?

I think so, I hope I haven't missed anything.

[Henry-E]

This looks good but we should give it a doc string similar to what the other macros have and maybe reference somewhere in the rest of the rust docs. I will look into adding this maybe.

Edit: Actually no, I see the doc string above the derive Init_space macro. That should surface on the front page of the rust docs.

[Aursen]

@Henry-E I added a test and fixed the issue normally

[Henry-E]

@Aursen final thing is just to add a changelog surfacing the new macro!

[Henry-E]

Thanks for the great work!