fix: more deprecation warnings for Gleam stdlib

[GearsDatapacks]

Hello, I'm back :) The stdlib deprecated more stuff

Pull Request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build-related changes
• Documentation content changes
• Other (please describe): Fixing deprecation warnings

What is the current behavior?

The code references deprecated stdlib types and values

Issue Number: N/A

What is the new

• The code now uses the new names and modules for those types/values

Does this introduce a breaking change?

• Yes
• No

The current version of glitzer uses gleam/iterator which is now deprecated in favour of gleam/yielder. It uses it in the map_iterator, map2_iterator and each_iterator functions. I have renamed these to *_yielder as that is a better description of their new behaviour. Users would have to use the new function names, and use the Yielder type instead of Iterator.

If you don't want to release a breaking change just yet, we could introduce these new functions in addition to the existing ones, but deprecate the ones that still use Iterator, removing them at a later date.

Other information

[miampf]

Hi, thanks again for your work :D . I'll probably take a closer look at it later this week

[miampf]

Decided to only deprecate the iterator functions since I do not want to introduce breaking changes out of the blue if it is not strictly necessary. I will make a minor release later and add an additional deprecation warning there, in the future (latest at the beginning of next year) I will make a major release that removes the iterator functions so that they do not clobber up the code base and so that people are encouraged more to move away from the iterator package. Thank you again for your PR!