## Description 

This PR adds a long-requested feature which is the ability to hover and
use go-to-def in the import (use) statements.

We now see on-hover information for identifiers in the use statements:
- for imported modules (including aliases)


![image](https://github.com/MystenLabs/sui/assets/1724397/096a1a4e-91f1-4111-9a4d-8fd8a1a5b56a)


![image](https://github.com/MystenLabs/sui/assets/1724397/e2361aa3-d8a1-4ee4-b21c-4b7927322e44)

- for imported types (including aliases)


![image](https://github.com/MystenLabs/sui/assets/1724397/4d445e22-f9c2-4e5b-8675-91cd61b72bdc)


![image](https://github.com/MystenLabs/sui/assets/1724397/28f639f9-aa27-46bc-934d-570c923f2c6b)

We also support go-to-def for identifiers in the use statements (modules
and types, including aliases)

## Test Plan 

New tests have been added.