Drop deprecated group' and mapWithIndex

[JordanMartinez]

Description of the change

Drop deprecated things

---

Checklist:

• Added the change to the changelog's "Unreleased" section with a reference to this PR (e.g. "- Made a change (#0000)")
• Linked any existing issues or proposals that this pull request should close
• Updated or added relevant documentation
• Added a test for the contribution (if applicable)

[JordanMartinez]

🏓 @thomashoneyman

[thomashoneyman]

You'll need to fix the import errors, but otherwise feel free to go ahead and merge!

 [1/4 UnusedImport] src/Data/List.purs:107:1

  107  import Data.FunctorWithIndex (mapWithIndex) as FWI
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  
  The qualified import of Data.FunctorWithIndex as FWI is redundant

[2/4 UnusedImport] src/Data/List.purs:118:1

  118  import Prim.TypeError (class Warn, Text)
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  
  The import of Prim.TypeError is redundant

[3/4 UnusedImport] src/Data/List/NonEmpty.purs:66:1

  66  import Data.FunctorWithIndex (mapWithIndex) as FWI
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  
  The qualified import of Data.FunctorWithIndex as FWI is redundant

[4/4 UnusedImport] src/Data/List/NonEmpty.purs:83:1

  83  import Prim.TypeError (class Warn, Text)
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  
  The import of Prim.TypeError is redundant