Replace FieldHook with FieldHookArgs in Typescript Section

[mrobst]

Typescript documentation shows import and use of FieldHook type which I think is incorrect and should be FieldHookArgs

Description

Documentation fix for typescript field hooks

• [X ] I have read and understand the CONTRIBUTING.md document in this repository.

Type of change

• [X ] Chore (non-breaking change which does not add functionality)

Checklist:

• [X ] I have made corresponding changes to the documentation