essentials2024.arr: provide string-{get-index,find{,-index,-opt}} from global

[ds26gte]

This PR has essentials2024.arr provide the functions

string-find
string-find-opt
string-find-index
string-get-index

from global. (This is similar to how starter2024.arr provides these functions.)

This has the effect of making these functions available from dcic2024.arr too.

This is a fix for the pyret-lang issue brownplt/pyret-lang#1824.

[jpolitz]

I don't think we should change existing contexts for this reason. There might be a bunch of people who already added these definitions to their code as abbreviations, etc. We would break all their code.

[ds26gte]

I don't think we should change existing contexts for this reason. There might be a bunch of people who already added these definitions to their code as abbreviations, etc. We would break all their code.

Oh, I was going by your statement that "it's reasonable to add string-find to both", where I thought the "both" referred to starter2024 and essentials2024...

[jpolitz]

Yeah I should have said “we should have added string-find to both” but I think that train has sailed. We will make a new context for next year, though, and can add it then.

[ds26gte]

A new PR #605, one that doesn't modify frozen context essentials2024, supersedes this one.

[ds26gte]

Deleting PR.