Replace usages and overrides of deprecated getSuggestions method

[SirYwell]

Overview

Description

As a follow up of #2613, we can replace the usages and overrides in FAWE code of the deprecated method. This should help to also make all the context-sensitive suggestions work better when nested in other constructs.

### Submitter Checklist
- [x] Make sure you are opening from a topic branch (**/feature/fix/docs/ branch** (right side)) and not your main branch.
- [x] Ensure that the pull request title represents the desired changelog entry.
- [x] New public fields and methods are annotated with `@since TODO`.
- [x] I read and followed the [contribution guidelines](https://github.com/IntellectualSites/.github/blob/main/CONTRIBUTING.md).