* Rename TypeDefinitionProvider to TypeImeplementationProvider

**bug**
In #18346, I originally called the new go to implementation provider api `ImplementationProvider` which we then decided to rename to `TypeDefinitionProvider`. At the time, I didn't realize that a type definition was actually its own, unrelated concept.

**Fix**
Rename `TypeDefinitionProvider` to `TypeImplementationProvider` to make it clear what the purpose and use of this api is.

* Fix a few names in comments

Extension Packs

Splits the markdown scroll sync settings to be more granular.

Fixes #19074

This may turn into an enum or change behavior soon pending on the result of
task-terminal integration. Removing from the API until more thought has been
put into it.

Part of #15583
Part of #18661

Move configuring language based settings to preferences and expose it as an API from preferences service

Fix for #16771.